摘要:

LE SUEUR : DIHYDROXYSTEARIC ACIb. 1313 CXXXVIIL-The Products o f the Action o f Fused Potassium Hydroxide on Dihydroxystearic Acid. By HENRY RONDELE SUEUR. Two papers communicated to the Society by Dr. Crossley and the author (Trans., 1899, 75, 161 ; 1900, '76, 83) contain details of ex- periments made in order to devise a method by which the constitution of fatty acids might be determined. I n this process, the fatty acid is first converted into an unsaturated acid with the double bond between the a- and P-carbon atoms and this acid is then oxidised with potass- ium permanganate in alkaline solution, whereby a dihydroxy-acid is produced, R*CH:CH*CO,H --+ R*CH(OH)*CH(OH)*CO,H, which on further oxidation with potassium dichromate and dilute sul- phuric acid is converted into a saturated acid containing two carbon atoms less than the original acid and oxalic acid or its oxidation products.R*CH(OH)*CH(OH)*CO,H +- R*CO,H + CO,H.CO,H ( + CO, + H,O). The final substance is not invariably an acid ; for instance, if the original acid is of the type R,CH*CH,*CO,H, the final oxidation product will be a ketone of the type R,CO (Trans., 1899, 75, 164). I n this method, the second oxidation, that with potassium di- chromate and dilute sulphuric acid, is carried out in an acid solution, and provided the dihydroxy-acid is soluble in such a solution, the method works well; if, however, it is insoluble, then the oxidation is very slow, and only a small part of the dihydroxy-acid is completely oxidised. It was thought that in such cases fusion of the dihydroxy- acid with potassium hydroxide might serve the same purpose as the oxidation with potassium dichromate and dilute sulphuric acid, and the work described in this paper was undertaken in order to see whether this assumption was correct.Dihydroxystearic acid was chosen because i t can be obtained fairly easily in large quantities and is in- soluble in water ; it was also hoped that the results obtained would furnish evidence from which the formula of dihydroxystearic acid and consequently that of oleic acid might be definitely established. For instance, using the generally accepted formula for the acid, oleic acid, CH,* [CH,]7*CH:CH*[CH,]7*C0,H, on oxidation with potassium per. manganate, should give dih ydroxystearic acid,1314 LE SUEUR: THE PRODUCTS OF THE ACTION OF FUSED which, on fusion with potassium hydroxide, would be broken up, yielding molecular quantities of pelargonic acid, CH,*[CH2I7* CO,H, and azelaic acid, C0,H*[CH2]7*C0,H, as the sole initial products.The pelargonic and azelaic acids might suffer further decomposition and the author has satisfied himself that such does actually happen in the case of the latter. The results obtained were unexpected, for instead of the final product being an acid or acids containing fewer carbon a t o m than the original substance, the main product was an acid containing the same number of carbon atoms, which clearly showed that, whatever may be the correct formula of dihydroxystearic acid, the main decom- position did not take place between the two carbon atoms to which the hydroxyl groups are attached.The result of the work described in this communication therefore apparently gives no clue to the constitu- tion of dihydroxystearic acid ; further investigation of the dibasic acid obtained may, however, furnish some evidence in this direction. The fusion of dihydroxystearic acid with pc?tassium hydroxide was first carried out a t 270--275", and the substances isolated from the product were found to consist mainly of an oil boiling a t 280-300° under 50 mm. pressure, together with small quantities of pelargonic and azelaic acids. The effect of carrying out the fusion a t a some- what lower temperature was next tried, when, as is described below, the following substances were isolated : A dibasic acid, ClsH3405, melting a t 1 11-111*5° ; an acid, Cl8HS4O3, melting a t 78.5-79O ; pelargonic acid; and azelaic acid.The first of these was obtained in a 58 per cent. yield of that theoretically obtainable and the other three only in small quantities. That the acid C,,H,,O, (m. p. 111-111*5°) is dibasic is clearly shown from the analysis of its salts, its titration with standard alkali, the determination of the molecular weight of its ethyl ester by the freezing point method, and also from its capability of forming an amic acid and a diamide. That it is also a monohydroxy-acid is shown from the fact that it yields a monoacetyl derivative on treatment with acetic anhydride or acetyl chloride. No mention could be found of the previous existence of this acid. Analyses of the acid C1sH3403 (m.p. 78*5-79O) and of its sodium salt gave numbers which agree closely with the calculated values for the formulae assigned to them. The acid may be regarded as an internal anhydride, formed by the eliminatian of one molecule of water from a molecule of dihydroxystearic acid : It was thought that such an acid would be reconverted into dihydr-POTASSIUM HYDROXIDE ON DIHPDROXYSTEARLC ACID. 1315 oxystearic acid by boiling with dilute acids or alkalis, but experiments carried out in this direction have so far proved unsuccessful. By the distillation of dihydroxystearic acid under reduced pressure, Saytzeff (J. p. Chem., lSS6, [ii], 33, 313) obtained an acid melting at 77-79' and solidifying a t 69-70', to which he assigned the formula C18H3,03. H e regarded it as an anhydride of dihydroxystearic acid formed as described above.But this acid must have been impure, because the numbers which Saytzeff obtained on analysis do not agree at all closely with those calculated for the formula C1sH340s, the mean of four analyses giving 70.91 per cent. of carbon, whereas the calculated amount is '72.49 per cent. It must, however, be stated that the sodium and silver salts on analysis gave numbers which agree well with those calculated for a monobasic acid of the formula Albitzky (J. Buss. Yhys. Chem. Xoc., 1899, 31, 76) has described glycidic acids of similar composition, obtained by the action of barium hydroxide on the chlorohydroxystearic acids. The formation of a monohydroxydicarboxylic acid from a di hydroxy- monocarboxylic acid is not easy to explain, unless it is assumed that the acid CI8H3*O3 is first formed and that this is immediately oxidised to the acid C18H3,0,.Thus C,BH9*0,* p 3 p 3 yo,= ( p 2 b ( p 2 b (QH,), qH*OH CH 7% (?HA ( p 2 ) n (FHA CO,H CO,H C02E YH-OH + QH>o + FH-OH EXPERIMENTAL. Prepayation of Dihydroxystewic Acid.-The acid was prepared by the oxidation of oleic acid with potassium permanganate in alkaline solution, a s recommended by Saytzeff (Zoc. cit.). Eighty-four grams of oleic acid (Kahlbaum's pure acid) were dissolved in 1500 C.C. of water containing 33 grams of potassium hydroxide, the solution was cooled to Oo, and a cold solution of 84 grams of potassium permanganate in 1500 C.C. of water gradually added, the mixture beiug well stirred by means of a turbine and its temperature maintained below loo.The whole was allowed to remain overnight, filtered from the separated manganese dioxide, and acidified with dilute sulphuric acid, when a very voluminous, white precipitate of dihydroxystearic acid separated out. This was filtered off, dried on a porous plate, and extracted with1316 LE SUEUR: THE PRODUCTS OF THE ACTION OF FUSED a small volume of ether in order to remove any unoxidised oleic acid. The residue (insoluble in ether) was recrystallised from rectified spirit until its melting point was constant, when 45 grams of pure dihydroxy- stearic acid were obtained, the yield amounting to 48 per cent. of that theoretically possible. Melting Point of Dihydroxystealr.ic Acid.-Various temperatures have been given as the correct melting point of pure dihydroxystearic acid.Saytzeff (Zoc. cit.), Hazura (Monatsh., 1888, 9, l86), and others, state that the acid melts at 136.5'; Edmed (Trans., 1898, 73, 629) gives 134O as the melting point, Groger (Ber., 1889, 22, 620) gives 130.5-131*5°, and lastly, Freundler (Bull. SOC. Chim., 1885, [iii], 13, 1052), who separated the acid into its optical isomerides, states that it melts a t 131'. I n view of these conflicting statements, it was deemed advisable to make every effort to ascertain the true melting point of the pure acid. The dihydroxystearic acid, obtained as described above, after two recrystallisations from rectified spirit melted at 1 30*5-131' (uncorr.), and after three further recrystallisations still melted a t this temperature.On analysis : 0.1500 gave 0.3754 CO, and 0.1536 H,O. The acid was then boiled with a large volume of water, in which it is insoluble, whereas the higher hydroxylated acids, such as sativic acid (tetrahydroxystearic acid), are somewhat soluble, and again re- crystallised from rectified spirit, when it still melted a t 130*5-131° (uncorr.). It was next boiled with ether, in which it is slightly soluble, and the ethereal solution filtered off from the undissolved por- tion. Both this undissolved residue and the acid obtained by evaporation of the ethereal solution melted at exactly the same tem- perature, namely, 130-5-1 31'. The dihydroxystearic acid, which was obtained by the author from the oxidation of the unsaturated acids of the oil of Cccrlhamus tinctorius, also melted a t this temperature (J.SOC. Chem. Ind., 1900,19,104). On applying the usual method for correcting the melting point of .a substance, 131.5-132' is obtained as the corrected melting point of pure dihydroxystearic acid. Calcium Salt of Dihydroxystearic Acid.-Saytzeff (loc. cit.) states that calcium dihydroxystearate, after drying in a desiccator, contains 1 mol. of water of crystallisation; Edmed (loc. cit.), on the other hand, states that the dried salt contains 3 mols., but from the following results it will be seen that the air-dried salt contains only 1 mol. of water of crystallisation. The salt was prepared by adding an aqueous solution of the potassium salt of the acid to an aqueous dution of calcium chloride, C = 68.25 ; H = 11.38.C18H,,0, requires c' = 68.35 ; H = 11 -39 per cent. On analycis :POTASSIUM HYDROXIDE ON DIHYPROXYSTEARIC ACID. 1317 0.4876, air-dried salt, a t 135O lost 0.0134 H,O. 0.4716 salt dried at 135' gave 0.1000 CaSO,. H,O = 2.74. Ca=6.23. (ClsH,,O,),Ca,HzO requires H,O = 2.62 per cent. ( C,S%O,) 2Ca ,, Ca ~ 5 . 9 7 ,, Fusion, of Dihydroxysteayic Acid with Potassium IIyd~*oxide.--Five grams of dihydroxystearic acid, 25 grams of pure potassium hydroxide, and sufficient water to form a thick paste, were well mixed togetber in a nickel crucible and heaked in a metal bath. At 200°, the mass com- pletely liquefied, and at 250' it turned slightly brown in colour and evolved a small amount of hydrogen. The temperature was then raised to 270-275' and maintained at this point until the rapid evolution of hydrogen which a t first took place had ceased. The product was then cooled, dissolved in water, acidified with dilute sulphuric acid, and subjected to steam distillation.The distillate contained pelargonic acid, which was identified by the melting point of its crystalline zinc salt, The residue in the flask contained a dark oil, which mas filtered off (filtrate=A) from the mother liquor, dried in a vacuum desic- cator, treated with ether, and the ethereal solution (filtered from a small amount of insoluble residue) evaporated, when 1.2 grams of an oil which distilled without decomposition a t 280-300° under 50 mm. pressure were obtained. Azelaic acid was isolated from the aqueous filtrate A and identified by its melting point (106") and analysis.The effect of carrying out the fusion at a somewhat lower tempera- ture was next tried, when it was found that no oil was produced, but that the acids left in the flask after steam distillation solidi6ed to n hard mass, which a t first was thought to be unchanged dihydroxy- stearic acid. This, however, was soon found not to be the case, as the substance is readily soluble in ether, in which dihydroxystearic acid is only slightly soluble, and on extracting the solid fractionally with chloroform two acids were obtained melting respectively a t 111-1 11.5' and 78.5-79O. I n order t o obtain larger quantities of these two sub- stances, 250 grams of dihydrosystearic acid were fused with potassium hydroxide in quantities of 40 grams at a time, the fusion being carried out as follows : 40 grams of dihydroxystearic acid, 200 grams of pure potassium hydroxide, and sufficient water to form a thick paste were well mixed in a nickel crucible and gradually heated in a metal bath, the mass being vigorously stirred the whole time, A t ZOOo, the mass liquefied and there was much frothing; the temperature was then raised to 250' and maintained a t this point until the frothing ceased, which took place after 20 minutes, during which time only traces of hydrogen were evolved.If the heating be continued, much hydfogen is evolved and the mass darkens. It is necessary that the fusion should be stopped the moment this second action sets in, otherwise the result-1318 LE SUECR: THE PRODUCTS OF THE ACTION OF FUSED ing substanoes are those described on page 1317.The fused product was dissolved in water, acidified with dilute sulphuric acid, and the liberated acids separated from the mother liquor and washed with boiling water. The whole of the mother liquor was extracted four times with a large volume of ether, when, on evaporation of the ethereal solution, 10 grams of a solid residue were obtained, which was readily soluble in hot water and crystallised out on cooling in large plates which melted at 105-106° and had all the properties of azelaic acid. On analysis : 0.1550 gave 0.3272 CO, and 0.1 182 H20. C = 57-57 ; H = 8.47. C,H1,O, requires C = 57.44 ; H = 8.51 per cent. On cooling, the acids liberated by sulphuric acid solidified to a hard mass, which was powdered, dried in a vacuum desiccator, and extracted with cold chloroform; the products soluble and insoluble in this solvent were then investigated.Product Insoluble in C'hhrofoTrn. The portion insoluble in chloroform was recrystallised from acetic acid until its melting point was no longer ohanged (111-111D50). Of the pure acid, 120 grams were obtained from 200 grams of dihy- droxystearic acid, a yield which corresponds to 58 per cent. of that theoretically obtaidable. On analysis : 0.1422 gave 0.3396 CO, and 0.1324 H,O. C = 65.13 ; H = 10.34. 0.1340 ,, 0.3210 CO, ,, 0.1256 H20. C=65.33 ; H=10*41. C18H3405 requires C = 64.45 ; H = 10.30 per cent, This acid is insoluble in cold water, but melts in boiling water. Its alcoholic solution gives a well-marked effervescence with a dilute solution of sodium carbonate or sodium hydrogen carbonate in the cold.It dissolves slowly in a cold solution of potassium hydroxide, and the solution thus produced does not affect potassium permanganate in the cold and reduces it only slightly on heating ; it is without effect on Fehling's solution. The acid is somewhat readily soluble in alcohol, ether, ethyl acetate, or acetone in the cold, and also i u hot acetic acid. It is insoluble in benzene, chloroform, or light petroleum ir, the cold, but dissolves readily in the former on heating. It crystal- lises from dilute alcohol or dilute acetic: acid in aggregates of long, flat needles melting a t 1 1 1-1 11 -59 2"iti~ttion of the Acid.-The acid was dissolved in alcohol which had been previously neutralised and the solution titrated with a deci- normal solution of potassium hydroxide.(i). (ii). 0.5614 ,, 34.2 c,c. ,, litmus ?, 0.41 12 required 25.23 c.c., using phenolphthalein as indicator,POTASSIUM HYDROXIDE ON DIHYDROXYSTEARIC ACID. 131 9 One gram of the acid therefore requires (i) 60.5 C.C. ; (ii) 60.9 c.c., the calculated amount for 1 gram of a dibasic acid, C,,H,,O,, being 60.6 C.C. The sodium salt was obtained as a hard mass of no very definite crystalline structure and could not be recrystallised from alcohol or water, owing to its great solubility. These remarks also apply to the neutral and acid potassium salts. The silver salt was thrown down as a white, curdy precipitate when a solution of the sodium salt was poured into excess of a warm solution of silver nitrate.C = 39.66 ; On analysis : 0.2310 gave 0.3360 GO,, 0.1238 H,O, and 0.0904 Ag. 0,1344 gave 0.0534 Ag. C,8H320,Ag2 requires C = 39.70 ; The barizcm salt was obtained as a white precipitate on the addit.ion The H = 5.95 ; Ag = 39.13. Ag= 39.73. H = 5.88 ; Ag = 39.70 per cent. of a solution of the sodium salt to a solution of barium chloride, salt was dried at looo and analysed : 0.2226 gave 0.1104 BaSO,. Ba = 29.20. C1,H3,O,Ba requires Ba = 29.52 per cent. The calcium salt was obtained as a white, gelatinous precipitate on the addition of a solution of the sodium salt to a solution of calcium chloride, The amount of water present in the air-dried salt was found to vary in different samples. In one case, numbers were obtained which agreed with those required for a salt of the formula C,,H~,O5Ca,3H,0.The air-dried salt loses the greater part of its water in a vacuum, but the last traces are only expelled at 155O. The salt was therefore dried at 155O, until no further loss occurred, and analysed : 0.2664 gave 0.0972 CaSO,. Ca = 10.73. 0.2176 ,, 0.0798 CaSO,. Ca=10.78. Cl,H3,0,Ca requires Ca = 10.87 per cent. Precipitates were obtained on the addition of an aqueous solution of the sodium salt of the acid to solutions of salts of mercury, copper, lead, manganese, iron, zinc, magnesium, cobalt, or nickel. Ethyl Estev, Cl,H820,(C,H,),.-The calculated quantity of ethyl iodide was added to the dry silver salt, which was covered with anhydrous ether in a flask attached to a reflux condenser and the whole heated on the water-bath for 22 hours.The resulting ethereal solution, which was of a bright yellow colour, due to finely divided silver iodide held in suspension, was evaporated, and the residual oil purified by distillation under reduced pressure. On analysis :1320 LE SUEUR: THE PRODUCTS OF THE ACTION OF FUSED 0.1526 gave 0.3816 CO, and 0.1490 H,O. It was also prepared directly from the acid as follows. C= 68.20 ; H = 10.85. C,,H,,05 requires C = 68.39 ; H = 10.88 per cent. Fifty C.C. of concentrated sulphuric acid were gradually added to a solution of 10 grams of the acid in 100 C.C. of absolute alcohol and the mixture allowed to remain at the ordinary temperature for 4 days and then heated on the water-bath for 3 hours. The product was poured into water, extracted with ether, the ethereal solution well washed with water, acd after evaporation of the solvent, the residual liquid was purified by fractional distillation under reduced pressure, when 7-2 grams, boiling at 268-274' under 31 mm.pressure, were obtained. The ester thus produced had a slight acid reaction, due no doubt to the presence of a trace of free acid or acid ester. The ester is a very faintly yellow, odourless oil boiling at 269-270O under 30 mm. pressure, and shows no signs of solidifying when strongly cooled or kept for several months. It is insoluble in water, but dissolves readily in ether, benzene, or alcohol. The molecular weight was determined by the freezing point method using benzene as solvent : Wt. of ester. Wt. of solvent. Depression.Mol. w t. 0.899 gram 20-83 grams 0.579O 365.2 1,4752 ,, 20.83 ,, 0.937 370.3 The molecular weight of C,,H,,O,(C,H,), is 386. The methyl ester, ClsH3,O5(CHJ,, was prepared by the action of On analysis : 0.1498 gave 0.3666 CO, and 0.1436 H,O. C,,H,,05 requires C = 67.04 ; H = 10.61 per cent. It is a colourless, oily liquid boiling at 258-259" unrler 30 mm. pressure and is insoluble in water, but dissolves readily in alcohol or ether. Amides.-Henry (Compt. rend., 1885, 100, 944) has shown that the diamides of the dibasic acids (succinic, adipic, &c.) are more easily prepared from the methyl than from the ethyl ester by the action of an aqueous solution of ammonia. Experiments made with the ethyl ester showed that this statement also applies to the acid C1,HS4O5, and the amides were consequently prepared from the methyl ester.Four grams of the methyl ester and 25 C.C. of an aqueous solution of ammonia, saturated at O', were heated together in a sealed tube at 185'for 12 hours. At the end of this time, the whole of the ester had disappeared, and a small amounb of solid mas present, which was fi1 tered off (filtrate = A), dried on a porous plate, and purified by re- crystallisation from rectified spirit. methyl iodide on the dry silver salt. C = 66.74 ; H = 10.65. On analysis ;POTASSIUM HYDROXIDE ON DIHYDROXY STEARIC ACID. 1321 0.1202 gave 8.9 C.C. moist nitrogen at 14' and 760 mm. C,8H360,Nz requires N = 8-54 per cent. The diamida is insoluble in water, ether, chloroform, or light petroleum, but readily dissolves in boiling acetone or alcohol, from the latter of which it separates in aggregates of fine needles melting sharply at 1 4 1 O .It is insoluble in an aqueous solution of potassium hydroxide, The yield was small, only 0.7 gram being obtained from 11 grams of methyl ester. The Amic Acid.-The filtrate (A) from the diamide was diluted with water and acidified with dilute hydrochloric acid, when the oil which separated out immediately solidified. It was filtered off, dried on a porous plate, and purified by recrystallisation from dilute alcohol. On analysis : N=8.71. 0.1478 gave 0.3556 CO, and 0.1410 H20, 0.1428 ,, 5.9 C.C. moist nitrogen a t 20' and '767 mm. N = 4.76. C18H,,04N requires C = 65-65 ; H = 3 0.64 ; N = 4.26 per cent. C= 65.61 ; H = 10.60. 0.2406 ,, 9.8 C.C.> ? ,, 17' ,, 764 mm. N=4*75. The amic acid crystallises from rectified spirit in aggregates of colourless needles melting a t 136'. It is insoluble in water, ether, chloroform, or light petroleum, but dissolves slowly in a solution of potassium hydroxide in the cold and readily on warming. Its alcoholic solution is acid to litmus paper and gives a marked effervescence with a solution of sodium hydrogen carbonate in the cold. Silvev Sak of the Amic Acid.-The amic acid was dissolved in dilute alcohol, neutralised with ammonia and the warm solution of the ammonium salt poured into an excess of a solution of silver nitrate, when the silver salt separated out as a somewhat sticky, white precipi- tate, which soon became hard and granular. The whole was heated nearly to boiling, filtered, and the precipitate washed with water and alcohol, dried, and analysed : 0-1476 gave 0.0368 Ag.Ag= 24.93. C18H3,0,NAg requires B g = 24.77 per cent, Action of Acetic ANhydride on the ,4cid.-Ten grams of the acid and 40 grams of acetic anhydride were boiled together for 3 hours in a flask attached to a reflux condenser. The acid readily dissolved in the anhydride on heating. On distilling the liquid product under 90 mm. pressure, the excess of acetic anhydride passed over below O', and the last traces of this substance were removed by raising the tempera- ture t o 130' for a short time and passing a slow current of dry air through the liquid. The acetylated product was then allowed to remain over solid potassium hydroxide in a vacuum for 4 days and analysed.The analytical results indicate that the substance is the1322 LE SUEUR: TEE PRODUCTS OF TEE ACTlON OF FUSZD monoacetylated clnhydkk, C,,H,,O,*Cc)*GH 3, and not the monoacetyl- ated acid, C,,H,,O,=CO*CH,. 0,1396 gave 0.3464 CO, and 0,1226 H,O. C=67.67; H=9.75. CzoHa40, requires C = 67-79 ; H = 9.60 per cent. C2,H3,O6 ,? C=64.51 ; H=9*01 ,, 2.1208 grams of the acetylated product were boiled for 5 hours with an excess of an alcoholic solution of potassium hydroxide. The alcohol was then evaporated off and the liquid acidified with dilute sulphuric acid and distilled with steam. The distillate required 50.17 C.C. of decinormal potassium hydroxide for neutralisation ; the acetic acid from 1 gram of the acetylated product would therefore require 23-65 C.C.I n a second experiment, the acetylated product, after removal of the excess of acetic anhydride by distillation in a vacuum, was repeatedly boiled with water to remove the last traces of this im- purity; it was then filtered a t 100" and dried in a vacuum over potassium hydroxide and sulphuric acid for 5 days. 1.9954 grams of this product were hydrolysed in the manner just described. The distiilate required 41 *9 C.C. of decinormal potassium hydroxide for neutralisation, whence 1 gram of the acetyl derivative would require 21.0 C.C. The calculated amount for 1 gram of the monoacetylated anhydride, C,,H,,O,, is 28.24 C.C. and for 1 gram of the monoacetylated acid, C20H3606, 26.8 C.C. These results are not in close agreement with the calculated values for the acetylated anhydride or acid, but they undoubtedly shorn that a monoacetylated derivative is formed by the action of acetic anhydr- ic!e on the acid.The oil left in the steam distillation flask solidified to a hard mass on cooling and after one recrystallisation from dilute alcohol melted a t llOo, which shows that the original acid is -obtained on hydrolysis of the acetylated product, The metylated anhydride is a very viscous, light yellow liquid, which shows no signs of solidification on long standing. It is readily soluble in alcohol or ether and dissolves slowly in aqueous potassium hydroxide. Action of Acetyl Chloride on the Acid.-Five grams of the acid and 26 grams of acetyl chloride were boiled together for 1 hour in a flask attached to a reflux condenser, when the acid slowly dissolved.The product was treated in a similar manner to that obtained by the action of acetic anhydride. On analysis : Ob181O gave 0.4446 GO, and 0.1570 H,O. C = 67.00 ; H = 9.64. C,,H,,O, requires C = 67.79 ; H = 9.60 per cent.POTASSIUM HYDROXIDE ON DIHYDROXYSTEARIC ACID. 1323 1.7238 grams of this acetylated compound were hydrolysed and treated in a similar manner to the product obtained by the action of acetic anhydride as described above. The distillate required 44.0 C.C. of decinormal potassium .hydroxide for neutralisation ; the acetic acid obtained from 1 gram would therefore require 25.5 C.C. The monoacetylated anhydride obtained by the action of acetyl chloride possesses the same properties as that obtained by the action of acetic anhydride.Product So Zub Ze in ClJoro f orm. The chloroform extract of the mixed acids (see p. 1318) on evaporation, left 37 grams of a residue which became semi-solid on standing. It mas subjected to steam distillation until the distillate was only faintly acid. From this distillate, ether extracted 4.5 grams of a liquid which had a strong odour of pelargonic acid and from this 1.8 grams boil- ing at 249-255' were obtained, and identified as pelargonic acid by analysis of the silver salt (Ag = 40.41 per cent.) and preparation of the zinc salt which melted a t 130'. Acid C,,H,,O,.-The oil which remained in the distillation flask partially solidified on cooling, and after spreading on a porous plate, yielded 16 grams of a solid material, which was then fractionally re- crystallised from dilute alcohol until a substance of constant melting point was obtained.The amount of pure substance thus isolated was small, only about 6 grams being obtained from 200 grams of dihy- droxystearic acid. On analysis : 0.1072 gave 0.2838 CO, and 0.1094 H,O. C = 72.20 ; H = 11.34, 0.0866 ,, 0*2288 GO, ,, 0.0888 H,O. C = 72.06 ; H = 11.39. C,,H,,O, requires C = 72.48 ; H = 11.41 per cent. The acid is sparingly soluble in cold light petroleum, but dissolves readily on heating. It is very readily soluble in chloroform, ether, ethyl acetate, or acetone in the cold, or in hot alcohol, and separates out from dilute alcohol in small but well formed plates, melting at 78*5-79', and resolidifying at 763-77'. The sodium salt was prepared by neutralising the acid with a warm solution of pure sodium hydroxide. A small quantity of alcohol was added to the solution, when, on cooling, the sodium salt separated out. It was recrystallised from dilute alcohol, from which it separated in glistening leaflets, which were dried at looo and analysed, 0,2064 gave 0.0458 Na,SO,. The sodium salt is sparingly soluble in cold water, but dissolves Na = 7.19. C,,H,,O,Na requires Na = 7-19 per cent.1324 RAMSAY: NOTE ON THE SUPPOSED FORMATION OF AN readily on heating, It is sparingly soluble in alcohol and insoluble in acetone. The following attempts were made to reconvert the acid C,8H,,0, into dihydroxystearic acid, but in all three cases it was recovered un- changed : (1) boiling the acid with a 2 per cent. solution of potass- ium hydroxide for 11 hours; (2) boiling the acid with 10 per cent. sulphuric acid for 12 hours; (3) heating 0.5 gram of the acid, 30 C.C. of water, and 2 grams of barium hydroxide in a sealed tube at 143O for 8 hours. The investigation of this acid is being continued. CHEMICAL LABORATORY, ST. THOMAS’S HOSPITAL, S.E.

ISSN:0368-1645    

DOI:10.1039/CT9017901313

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

1324 RAMSAY: NOTE ON THE SUPPOSED FORMATION OF AN CXXX1X.-Note on the Supposed Formation of a.n Oxide of Hydrogen higher than the Dioxide. By WILLIAM RAmsAP, F.R.S. THE possible existence of a higher oxide of hydrogen than H,O, was suggested by A. Bach (Bey., 1900, 33, 1506) on the ground that when hydrogen peroxide is diluted with sulphuric acid, and treated with permanganate, the amount of oxygen evolved is in all cases greater than would have been produced, reckoning from the amount of per- manganate used. Now, as Armstrong has justly pointed out (Proc., 1900, 16, 134), Bach has failed to take into account the persulphuric acid, proved by Lowry and West to be formed by mixing hydrogen peroxide with sulphuric acid. But neither Armstrong nor Lowry and West have disproved Bach’s contention that a peroxide may possibly exist.The following account of some simple experiments will, I think, render Bach’s contention untenable. 1. The amount of oxygen liberated on addition of hydrogen peroxide to a mixture of permanganate and sulphuric acid is considerably greater than if the permanganate be added to a mixture of hydrogen peroxide and sulphuric acid. Thus, 2.2 C.C. of a dilute solution of peroxide, added to excess of permanganate, acidified with dilute sulphuric acid, gave 43.49 C.C. and 43.76 C.C. of oxygen; on adding the permanganate to a mixture of sulphuric acid and peroxide, 33.47 C.C. and 33.59 C.C. of oxygen were collected. 2. Less permanganate is required if it be added t o a mixture of hydrogen peroxide and sulphuric acid than if peroxide be added to a mixture of permanganate and sulphuric acid.For example :OXIDE OF HYDROGEN HIGHER THAN THE DIOXIDE. 1325 2.2 C.C. of peroxide mixed with sulphuric acid required 20.1 C.C. of permanganate ; on the other hand, 40 C.C. of permanganate mixed with sulphuric acid required 9.2 C.C. of peroxide. If, however, an acid, un- attackable by permanganate, be substituted for sulphuric aeid-and one which is incapable of a higher stage of oxidation-tbe percentage of hydrogen peroxide calculated from the permanganate taken is in sub- stantial agreement with that calculated from the oxygen evolved, in whichever order the reagents are mixed. To illustrate this statement, the following figures, obtained by the use of acetic acid, may be adduced : Ten C.C.of a dilute solution of hydrogen peroxide, mixed with acetic acid, required 12.3 C.C. of a solution of permanganate, containing 0.00669 gram KMnO, per c c. The peroxide solution, therefore, con- tains 0.0044 gram per C.C. Ten C.C. of the same peroxide solution, mixed with 12.3 C.C. of per- manganate containing acetic acid, gave 26.0 C.C. of oxygen, calculated to normal temperature and pressure. This corresponds to 0.0042 gram per C.C. Another solution of permanganate was made, containing 0.00694 gram per C.C. ; with this, the amount of available oxygen in 10 C.C. of a solution of peroxide was determined by addition of peroxide t o a mixture of permanganate and sulphuric acid; i t amounted to 0.0354 gram, Five experiments mere then made, in which the peroxide was added t o a mixture of permanganate with acetic acid; and five in which the permanganate was added to a mixture of peroxide and acetio acid; the oxygen was collected and measured in each case, and its weight calculated.The results are given in the following table : Peroxide Difference Perniangariate Difference added. per cent. added. per cent. 1. 0.0365 + 3.71 1. 0.0351 - 0.34 2. 0*0350 - 0.89 2. 0.0350 - 0.89 3. 0,0350 - 0‘89 3. 0.0349 - 1.27 4. 0.0351 - 0.72 4. 0.0349 - 1.38 5. 0.0355 + 0.42 5. 0.0354 + 0.20 The small error is probably to be ascribed to the solubility of the liberated oxygen in the liquid. One other experiment remains to be chronicled ; Baeyer’s statement, that neither persulphuric acid nor Caro’s acid rapidly affects permnn- gmate, was confirmed (Bey., 1901, 34, 853). Having added permanganate of known strength to a mixture of peroxide and sulphuric acid, he imagined that he had determined the strength of the peroxide solution. But, in actual fact, he had used too little permanganate, owing to the formation of persulphuric acid, and thus he reckoned the amount of peroxide as smaller than it really was. The oxygen collected on adding Bach’s results are now explicable. VOL. LXXIX. 4 Y1326 HOLROYD : THE ELECTROLYTIC REDUCTION OF NITROUREA. the peroxide to the mixture of permanganate and sulphuric acid was therefore too great for the apparent weight of peroxide present in solution, and so he was led to imagine the existence of a peroxide of hydrogen containing more oxygen than the dioxide. My thanks are due to Messrs. H. Tempany, W. J. St. J. Alton, A. 0. Jones, and A. C. Carter for carrying out the experiments de- scribed in this note. UNIVERSITY COLLEGE, LONDON.

ISSN:0368-1645    

DOI:10.1039/CT9017901324

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

1326 HOLROYD : THE ELECTROLYTIC REDUCTION OF NITROUREA. CXL-The Elec t ro 1 y t ic Reduction of Nitrourea. By G. W. F. HOLROYD. THIELE AND LACEMAN (Annnlen, 1895, 288, 303) obtained evidence of the formation of nitrosourea as the primary reduction product of nitrourea. This nitroso-compound appears to be very unstable, being readily decomposed by mineral acids or acetic acid, and although rather more stable in alkaline solution, i t decomposes, even in such a solution, a t a little above 0". With the object of reducing the nitrosourea before it decomposes and so preparing sernicnrbazide from nitrourea, Thiele and Heuser jibid., 311) added, in small quantities a t a time, a mixture of nitrourea and hydrochloric acid to a mixture OF zinc dust and ice. Since the temperature must be kept a t about O", this operation is very laborious.The semicnrbazide was separated from solution in the form of the compound [(CH,),C:N*NH-CO-NH,],,ZnCl, ; the yield of this com- pound obtained by the authors was 40 to 55 per cent. of the calculated amount. The experiments described below were undertaken in order to see whether the conditions necess;try for the reduction might not be obtained more easily by using the electric current. The result was to show that the reduction may be effected electrolytically with the expenditure of very little labour. An aqueous solution of ammonium chloride served, in the majority of experiments, as the electrolyte. The following are the conditions which I found most favourable for the reduction. Ten grams of nitrourea, prepared according to Thiele and Lachman's directions (Zoc.cit., ZSl), are placed in a jar, and 80 grams of commercial ammonium chloride and 300 grams of water are added. The cathode and anode each consist of a sheet of wrought iron, the area of one side of the portion of each of these which is immersed in the liquid is 70 sq. cm. The anode must be at least 3 aHOLROYD : THE ELEeTROLYTIC REDUCTION OF NITROUREA. 1'321 mm. thick, The cell is immersed in a large vessel of cold water. Since the resistance of such a cell, although it increases as the electrolysis proceedg, does not exceed more than about one ohm, a large number of such cells can easily be arranged in series, the anode of one cell being bent round so as to dip into the next and form the cathode of this second cell, and so on.I n experiment 15, several cells of double the size and with double the charge of nitrourea, ammonium chloride, and water mere placed in series. The yield given in the table refers to one of these cells; the rest of the product obtained in this experiment was not re- crystallised. After interrupting the current, the contents of the cell are filtered a t the pump, the precipitated ferrous hydroxide is washed twice with water, the turbid filtrate rendered clear by acidifying with hydro- chloric acid, the liquid again filtered if necessary, and 10 grams of benzaldehyde are added for every 10 grams of nitrourea used, in order to separate out the semicarbazide. The mixture is shaken in a bottle for a few minutes, allowed to stand for an hour, and the precipitated benzylidenesemicarbazide is then filtered off and mashed with water. The benzylidenesemicarbazide so obtained may be directly con- verted into semicarbazide hydrochloride, According to Thiele and Stange (Annalen, 1894, 283, 21), benzylidenesemicarbazide gives 89 per cent.of the theoretical yield of semicarbazide hydrochloride. If the benzylidenesemicarbazide is required in a state of purity, it may be recrystallised from commercial alcohol (methylated spirit). The reduction gave a yield of recrystallised benzylidenesemicarbazide equal t o 60 per cent. of the theoretical yield. The crude product probably contains 66 per cent. of the calculated amount, for 1 gram of pure benzylidenesemicarbazide gave 0.9 gram when recrystallised in the same manner.I found this the most economical method of preparing semicarbazide hydrochloride. Subjoined is a table showing the results of electrolysis under various conditions of temperature, size of electrodes, and density of current. In calculating the density of current, both sides of the cathode have been counted as area of the cathode, with the exception of those cases where the iron box was used and of experiment 17, where the electrodes were very close to one another. For purposes of estimation, the semicarbazide was converted into the benzylidene derivative. 0.1160 of the product in experiment 15 gave 26.1 C.C. of nitrogen at 17' and 758 mm. A current of 2 amperes is passed during 20 hours. N = 26.05. C8H90N, reyuiies N = 85-76 per cent. 4 Y 2Nature of electrolyte.24 grams of amuionium chloride, 90 grams of water. 9 1 I , , I 9 , I 9 8 grams of ammonium chloride, 30 grams oi water. Nature and size of electrodes. Cathode, a wrought iron box containing the electrolyte, 115 sq. cm. in con- tact with liquid ; anode, 70 sq. cm. wrought iron. Cathode same as in 1, with iron plate at- tached ; total area, 286 sq. cm. ; anode Cathode and anode ( as in 1. S Y Cathode as in anode, 360 sq. ci!] wrought iron. Cathode, a strip of wrought iron 15 sq. cm. ; anode as in 1. Cathode, a strip of wrought iron 7 sq. cm. ; anode as in 1. I (Ca;l$e and anode as i I.. 0, 2 -4 __ 1 1 1 1 1 1 1 1 1 1 3ensity of xirrent in amperes )er sq. cm. of cathode. 0.0087 0.0035 0.0087 $ 9 , 9 0,066 0'143 $ 9 0.066 Y , Per cent. of current effective in producing semicarb- azide. 12.9 12'1 19.6 12 -7 20.3 15 *7 18.4 16.08 29 -9 22 *5 Hours during which current was passed.6 9 ) 4 6 4 6 4 6 2 4 Grams of iitrourea used. Grams of recrystal- lised benzyl- denesemi- :arbazide. 0.79 0.74 0 '80 0'78 0.83 0 '96 0 *75 0'98 0.61 0.92 - 'er cent. of ;heoreti- cal yield. 5.0 9 47.7 51 *6 50 *3 53 -5 61.9 48 '4 63 -2 39 -35 59.3511 12 13 14 15 16 17 18 19 20 I 24 grnms of ammonium chloride, 90 grams of water. 80 grams of ammonium chloride, 300 grams of water. 150 grams of ammonium chloride, 600 grams of water. 26 grams of ammonium chloride, 73 of water, 22 of ammonia of sp. gr. 9 , o.aao. 8 grams of ammonium chloride, 25 of water, 5 of ammoi~ia of sp. gr. 0'880 (the nitrourea was added gradual 1 y. ) 50 grams of sodium chloride, 150 of water in outer cell; same solution in a porous inner cell.200 grams of 18 per cent. hydrochloric acid in outer cell ; hydrochloric acid of same strength in inner porous cell. 200 grams of 18 per cent. hydrochloric acid in outer cell ; hydrochloric acid of same strength in inner cell Cathode, a strip o wrought iron 30 sqfi cm. ; anode, 70 sq. cm. wrought iron. Cathode and anode as Cathode, a wrought iron plate 150 sq. i cm. ; ailode, ditto. Cathode, a wrought iron plate 300 sq. ~111. ; anode, ditto. The electrodes mere sheets of zinc; 70 sq. cm, of each were in contact with the liquid. The electrodes were discs of zinc placed oneabove theother, the area of one side of each was 50 sq. [Catho,de, platinum foil 72 sq. cm. in outer cell ; anode, carbonin inner cell.Cathode and anode as ,, I I in 18. 2 0 9 2 2 3 4 5 1.9 1.9 1.9 9 9 0.02 0.013 9 , 0'01 0'114 0.1 0'026 2 9 9 9 16.3 24 22 '9 18.1 2141 7.7 13'6 17-4 15.4 6 '4 3 15 20 25 27 20 14 8 ? l $ 9 I9 39 10 3 , 20 10 1 5 J f 2 1'0 1 *1 9 *34 9.24 1746 0'928 2.69 2.39 0.99 64.51 70.9G 60.25 59.61 56-32 40'58 59.9 34.7 30.8 32 -11330 HOLROYD : THE ELECTROLYTIC REDUCTION OF NITROUREA. I n experiment 16, the electrolysis was interrupted after 10 hours and begun again on the following day ; the nitrourea was added in portions of 1 gram at intervals of 2 hours. When electrolysis was at an end, the solution mas filtered and 5 grams of acetone were added, a crystalline deposit of the compound [(CH,),C:N*NH*CO*NH2]2,ZUC12 was formed. This precipitate was filtered off after some hours, and dried on a porous plate; it then weighed 5.95 grams.One gram of this precipitate was dissolved in water, 1 gram of benzaldehyde added, and the solution heated to boiling ; the benzylidenesemicarbazide thus formed was collected and recrystallised from alcohol ; it then weighed 0.73 gram. The 5-95 grams of zinc compound mould, therefore, have given 4.34 grams of recrystnllised benzylidenesemicarbazide ; this corresponds to a yield of 28 per cent. of the theoretical. 1-95 grams of recrystdlised benzylidenesernicarbazide mere obtained from the filtrate from the zinc compound ; this corresponds to a yield of 12.58 per cent. A total yield of 40.58 per cent. of the theoretical was, therePore, obtained in this experiment. In all the other experiments, the semicarbazide was precipitated directly as the benzylidene derivative.Experiment 17 shows that a good yield may be obtained when zinc poles are used, if the nitrourea be added very gradually. In the case of experiments 16 and 17, where zinc poles mere used, an alternating current was employed to prevent the formation of a bridge of zinc from pole to pole. A little piece of apparatus which I found very useful for alternating a direct current, depends on an observation made some yeara ago by Mr. A. G. Vernon Harcourt. If a vessel containing air be heated and connected, by means of glass tubing, with a U-tube containing mercury,JOWETT : THE CONSTITUTION OF PILOCARPINE. PART III. 1331 and :in oscillatory motion be imparted to the mercury, this motion is maintained so long as the vessel containing air is heated.I proposed to use this arrangement as a source of energy to work an ordinary rocking alternator, I am, however, indebted to Mr. D. H. Nagel, of Trinity College, for the suggestion that I should use the oscil- lating mercury in the U-tube directly for making and breaking contact. This I did in the following manner. I placed a flask of 250 C.C. capacity in a horizontal position above an argxnd burner and connected it, by means of a doubly-hored cork and bent glass tubes, with two U-tubes half-filled with mercury. By im- parting simultaneously to the mercury in both U-tubes an oscillatory motion (by depressing the mercury in the outer limbs by two corks fixed on theends of little rods), I obtained the necessary movement of the mercury. This movement is maintained so long as t h e flask is heated. By the arrangement of wires shown in the figure (p. 1330), a current may be sent first in one direction and then in the opposite direction through an electrolytic cell. The wires which come in contact with the mercury should be of iron. Thiele and Lachman remark with respect to primary nitrosoamines : ‘‘ These nitrosoamines are generally very unstable bodies, and it is owing to their production that the reduction of primary nitroamines generally gives such unsatisfactory yields ” (Zoc. cit.). A method similar to the above may probably be applied with advan- tage to the reduction of other nitroamines and nitrosoamines. This I hope to test in the near future. I wish to express my thanks to Mr. I). H. Nagel, of Trinity College, Oxford, for kindly allowing me to carry out these experiments in the Laboratory of Balliol and Trinity Colleges. CHRIST CHURCH, OXFORD,

ISSN:0368-1645    

DOI:10.1039/CT9017901326

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

JOWETT : THE CONSTITUTION OF PILOCARPINE. PART III. 1331 CXLI. -The Constitution of Pilocarpine. Part 111. By HOOPER ALBERT DICKINSON JOWETT. IN previous papers (Trans., 1900, 77, 851, this vol., 580), it was shown that by the oxidation of isopilocarpine with permanganate a small quantity of acetic acid is formed together with a crystalline lactonic acid, C,HI0O4, to which the name pilopic acid was assigned. The present paper deals with a fuller examination of the products of oxidation of the alkaloid and with the constitution of pilopic acid,1332 JOWETT : THE CONSTITUTION OF PILOCARPINE. PART III. By the oxidation of larger quantities of isopilocarpine, it has been found t h a t in addition to the acids above mentioned, small quantities of propionic acid and of a new acid, homopilopic acid, C8HI2O4, homologous with pilopic acid, are also obtained.Although the correctness of the formula for pilopic acid has been ques- tioned by.Pinner and Kohlhammer (Ber., 1900, 33, 1424, 2357; 1901, 34, 727), its accuracy has been confirmed, not only by analyses of the ethyl and methy I esters and of the crystalline acid and various deriva- tives, but particularly by the determination of the molecular weight of the methyl ester. The pure crystalline acid has been characterised and the anilide and the strychnine salt prepared in crystalline form and examined. The lactonic nature of pilopic acid has been proved by the preparation of the barium and silver salts and of the crystalline diamide of the corresponding hydroxy-acid, the behaviour of the acid in the last case recalling that of isohexolactone, which with ammonia yields y-hydroxyisohexoamide.The reaction may .be expressed by the following equation : CO C0,Et*C5H,< I 0 + ZNH, = OH*C5H9(CO*NH2), + Et*OH. Homopilopic acid has not been crystallised, but the diamide of the hydroxy-acid has been obtained in well-defined crystals and the lactonic nature of the acid proved by the preparation of the barium salt of the hydroxy-acid. It is also shown that there are grounds for regarding Pinner and Kohlhammer's piluvic acid as a mixture of pilopic and homopilopic acids. In a previous paper (Trans., 1900, 77, 858), it was shqwn that from ethyl pilopate, by treatment with phosphorus pentabromide, &c., a small quantity of isobutyric acid was obtained.Repetition of this experiment with a larger quantity of material and the isolation and examination of the intermediate products of the reaction have shown that the quantity of isobutyrie acid formed is very small and is pro- duced by secondary reactions. As the constitutional formula previously propoaed for pilopic acid was founded on the production of isobutyric acid as the main product of the reaction, the deductions are invalid and the formula must therefore be abandoned. By fusion of pilopic acid with potassium hydroxide a t a high temperature, normal butyric acid is formed, whilst at a low temperature most of the acid is not attacked, but a small portion is converted into the isomeric unsaturated acid. When homopilopic acid is fused with potassium hydroxide at a medium temperature, a-et~yZtricarbaZZyylic acid is produced, and this acid has been identified beyond question by the formation of certain characteristic derivatives (see following paper).JOWETT : THE CONSTITUTION OF PILOCARPINE.PART 111. 1333 Finally, i t is shown that in all probability the constitution of pilopic and homopilopic acids may be represented by the following formulae : C,Hb*YH- YH*CO,H C,H,*$XC-~H*CH,*CO,H CO*O*CH, CO*O*CH, Pilopic acid. Homopilopic acid. EXPERIMENT A L . Oxidation of is0 Pilocarpine and fownation of Propionic Acid. About 1 kilo. of isopilocarpine nitrate was oxidised with perman- ganate in the manner previously described, with this modification- that all the volatile acids formed were removed by steam distillation of the acid liquid previous to concentration and subsequent extraction with alcohol.The aqueous solution of the volatile acids, which was free from any rancid odour, was neutralised and evaporated t.0 a low bulk, acidified with sulphuric acid, and extracted with ether. After removal of the ether by evaporation, the residue, which smelt strongly of acetic acid, was distilled. The first fraction, which came over below 120°, consisted chiefly of acetic acid and was not further examined. The remainder of the liquid distilled completely between 120' and 140°, the greater portion coming over at 136'. The distillate was converted into the crystalline barium salt, from bhich the silver salt was obtained in three fractions by precipitation with aqueous silver nitrate. Each fraction was analysed with the following results : Fraction 1.0.2706 gave 0.1616 Ag. Ag=59-7. ,, 2. 0.1116 ,, 0 0666 Ag. Ag=59.7. ,, 3. 0.061 ,, 0.0366 Ag. Ag=60*0. C,H50,Ag requires Ag = 59.7 per cent. I n order to complete the proof of the identity of the acid, it was converted into the anilide, which melted a t 103', and on analysis furnished the following result : 0.1542 gave 13.6 C.C. nitrogen at 15' and 753 mm. C,H,,ON requires N= 9-4 per cent. N = 10.0. The only volatile acids formed during the oxidation of isopilocarpine with perrnanganate are therefore acetic and propionic acids, Pvactional Distillation of the Ethyl Esters. I n order to determine the composition of the ethyl ester obtained by the oxidation of isopilocarpine, it was submitted to careful fractionation.One hundred and thirty grams of the crude ester were twice1334 JOWETT : THE CONSTITUTION OF PILOCARPINE. PART III. refractionated under 10 mm. pressure and the following fractions obtained. Below 160'. ..... 20 grams 170-L75'. ..... 22 grams 160-165 '...... 10 ,, Above 175 O...... 12 ,, 165-170 O...... 52 ,, The fractionation in a vacuum was found to be unsatisfactory, as any slight variation in the pressure, which is almost unavoidable, affected the distilling point to a considerable extent. An attempt was made to fractionate the ester under the ordinary pressure, using the rod and disc fractionating apparatus (Young, Trans., 1899, 75, 689) and a metal bath. This method, however, was only partially successful, owing to the risk of fracture of the flask by the high boiling liquid and to the loss of valuable material by de- composition in each distillation.If a small quantity, for example, 20 grams, of the ester be rapidly distilled from an ordinary distilling flask, it appears to boil quite constantly at 299' with very little de- composition, and a simiiar result is obtained by distilling it in a vacuum. As the result of three fractionations, the whole of the liquid was separated into three main fractions, which were analysed with the following results : Fraction 1. B. p. 290-300' (or 164-166' under 10 mm. pressure). Fraction 2. B. p. 300--310'. Fraction 3. B. p. 310-312' (or 210' under 10 mm. pressure). 0.2126 gave 0.4544 CO, and 0.1446 H,O. 0.2102 gave 0.4544 CO, and 0.152 H20. 0.1538 gave 0.338 CO, and 0.1126 H,O.C = 58.3 ; H = 7.6. C=59*0; H=8*@. C = 59.9 ; H = 8.1. C, H,,O, requires C = 58.1 ; H = 7.5 per cent. CIoH,,O, ,, C=60.0; H=8*0 ,, C,2H2005* ,, 0=59*0; H=802 ,, The greater portion of the ester was contained i n fractions 1 and 2. From these results, i t would appear-that two homologous esters are present, the first and third fractions each consisting of an almost pure ester and the second fraction being a mixture. This will account for the high figures persistently obtained for the carbon, as it is almost impossible to procure the lower fraction quite free from the higher homologue. The first fraction on hydrolysis readily yields the crystalline pilopic acid, but the second and third fractions only yield an oil which could not be crystallised.By distillation of the second fraction in a vacuum, it was possible to * Pinner and Kohlhammer's formula.JOWETT : THE COXSTITUTION OF PILOCARPINE. PART 111. 1335 effect a separation into three fractions, similar to those previously described, thus proving it to be a mixture of the two homologous esters. Pilopic Acid, C7H,,0,. This acid, which was crystallised with considerable dificul ty, was prepared as follows. The ethyl ester boiling a t 290-300° was hydrolysed either by aqueous potassium hydroxide or by 40 per cent. sulphuric acid, and the acid liquid saturated with ammonium sulphate and extracted by ether, The ethereal solution of the acid was next extracted with sodium carbonate solution, and the alkaline liquid sub- sequently acidified with sulphuric acid, saturated with ammonium sulphate, and extracted by ether. The ethereal extract was washed with water, dried over calcium chloride, and distilled.The syrupy residue, after standing for several days in a vacuous desiccator over sulphuric acid, with frequent stirring, became pasty and almost solid. It was spread on a porous tile, and the crystalline crust thus obtained recrystallised several times from hot benzene. After several recrystal- lisations, it separated in silky plates melting constantly at 104' (cow,). The acid can also be crystallised from water, in which, however, it is very soluble. On analysis : 0.09 gave 0.1748 CO, and 0.0526 H,O. C=53-0 ; H = 6 - 5 . 0.1528 ,, 0.297 CO, ,, 0.0904 H,O. C = 53.0 ; H=6.57. C7Hlo0, requires C =53*2 ; H= 6.3 per cent.The acid is dextrorotatory, and a determination of the specific rotation in aqueous solution gave the following result : uF= +1*2O; Z=1 dcm.; c=3*324; [u]F= +36*1". When excess of alkali is added to the acid solution, the specific rota- tion diminishes, a property also shown by pilocarpine and isopilocar- pine, A determination of the specific rotation in alkaline solution gave the following result : a;'= +0*3O; Z=1 dcm.; ~ = 9 * 5 ; [ a ] g " = + 3 * 2 O . The methyl ester, prepared in the usual way by means of sulphuric acid and methyl alcohol, is a colourless liquid boiling at 155-160° under 10 mm., and at 275" under 757 mm. pressure. On analysis : 0,1534 gave 0.315 GO, and 0.099 H,O. C8Hl,0, requires C=55.8; H='7-0 per cent. I n order t o prove conclusively the correctness of the formula C7Hl,0,, proposed for pilopic acid, the molecular weight ot the methyl ester was determined.Although the percentages of carbon and hydrogen required for the formulze proposed by the author and by C=56.0; H = 7.2.1336 JOWETT : THE CONSTITUTION OF PILOCARPINE, PART 111. Pinner and Kohlhammer are not very dissimilar, there is a consider- able difference in the molecular weights of the corresponding ester. The molecular weight was determined by the depression of the freezing point of benzene and of glacial acetic acid, Solvent. Wt. of ester. Wt. of solvent. Depression. Mol. wt. Benzene ... .. . ... 0,3322 13.98 0.65" 179 Glacial acetic acid 0.3964 15.762 0.59 166 Molecular weight of C,H,,O, = 172 9 , ,, CloH,60, = 216 (P.and K. formula) These results, in addition to the analytical data recorded in this paper, conclusively prove the correctness of the formula C7Hlo0, pre- viously ascribed to pilopic acid. The bwrium salt of pilopic acid was prepared by digesting an aqueous solution of the acid with excess of barium carbonate, filtering, evaporating the filtrate to a low bulk, and precipitating with alcohol. The microcrystalline salt, dried at 120°, was analysed with the fol- lowing result : 0.1406 gave 0.0722 BaSO,. (C7H,0,),Ba requires Ba = 30.4 per cent. The anilide, C7H,0*NH*C,H,, was prepared by boiling the acid with three times its weight of aniline in a reflux apparatus for 24 hours. The liquid was poured into excess of dilute hydrochloric acid and the acid liquid extracted with ether.The ethereal extract was washed four times with dilute acid, finally with water, and dried over calcium chloride. After removal of the ether by distillation, the residue was placed in a vacuous desiccator over sulphuric acid and frequently stirred. In a short time, the oil became almost solid ; the mass was spread on a porous tile and the dry powder then recrystallived from hot ether until of constant melting point. It was thus obtained in white, flat, pearly plates melting sharply a t llOo (corr.). On analysis : Ba = 30.2 0.1124 gave 6.4 C.C. nitrogen at 22' and 764 mm. The strychnine salt was prepared by boiling the aqueous solution of tho acid with excess of strychnine and filtering. The filtrate was then evaporated in a vacuous desiccator over sulphuric acid and a very hygroscopic crystalline mass obtained, which was dissolved in a little hot alcohol. On standing, after the addition of ether, a quantity of strychnine separated, which was removed, and more ether added to the mother liquor.After long standing in a stoppered bottle, rosettes of crystals separated. These were dried and found to be very soluble in N = 6-3. CI8Hl5O,N requires N = 6.0 per cent.JOWETT : THE CONSTITUTION OF FILOCARPLNE. PART III. 1337 water or alcohol and t o melt at 120" (corr.) ; the aqueous solution was acid to litmus. On analysis : 0.186 gave 7.6 nitrogen at 2 2 O and 764 mm. N=4-5. 0.1606 ,, 0-0832 anhydrous strychnine = 51.S. C,,H2-,0,N2(C7Hlo0,), requires N = 4.3 ; strychnine = 51 *4 per cent. This was therefore the acid salt of strychnine, formed by the separation of strychnine from the normal salt which was apparently first produced.The diamide of the hydroxy-acid was prepared by mixing equal volumes of the methyl or ethyl ester of pilopic acid and strong aque- ous ammonia. After standing for some hours with frequent shaking, the oil disappeared and the liquid solidified to a mass of crystals which was drained on a porous tile and recrystallised from hot alcohol until of constant melting point. The amide was sparingly soluble in cold water or alcohol, fairly so in hot water or alcohol, and almost in- soluble in ether, benzene, or chloroform. The crystals melted a t 160" (corr,), and on analysis yielded the following results : 0.0934 gave 0.167 CO, and 0.069 H,O. 0.1206 ,, 17.0 C.C.nitrogen a t 14" and 764 mm. N = 16.4. C7H,,0,N2 requires C = 48.3 ; H = 8.1 ; N = 16.1 per cent. Lactonic character of Pilopic Acid.-The correctness of the formula for pilopic acid having been demonstrated, experiments were next undertaken to obtain further proof of its lactonic character. Two grams of the acid were boiled with excess of baryta water for an hour, the solution saturated with carbon dioxide, and filtered. The filtrate was evaporated to a low bulk, acidified with the requisite quantity of sulphuric acid, and extracted with ether. The ethereal solution was washed with water, the ether spontaneously evaporated, and the residue placed overnight in a desiccator over sulphuric acid. It was then titrated with normal alkali, using phenolphthalein as indicator, with the following reaults : 0.52 required in the cold, 3.4 C.C.for neutralisation, and, when boiled with excess of alkali and titrated back with acid, 6.5 C.C. ; this amount of an acid, C7H1,,O4, requires 3.3 C.C. and 6.6 C.C. respectively. The substance was therefore the lactonic acid. The burium salt of the hytlroxy-acid mas prepared by adding alcohol to a concentrated aqueous solution of the salt, prepared as just described. The precipitate was filtered off and dried on a porous tile. On analysis, the air-dried salt yielded the following result : C=48.7; H=8*2. 0.1404 gave 0.0982 BaSO,. Bit = 41.1. 0.258 at 150" lost 0.0112 H,O. H,O= 4.4. C7H,00,Ba,H,0 requires Bs = 41.6 ; H,O = 5.5 per cent.1338 JOWETT : THE CONSTITUTION OF PILOCARPINE.PART 111. The specific rotation of the barium salt was determined in aqueous solution with the following result. ah@= +0*216O; 1 = 1 dcm,; c=3*512 ; [a]':= +6.1°. The silver salt of the hydvoxy-acid, prepared from the barium salt by interaction with silver nitrate, was a gelatinous precipitate, which, after drying on a porous tile, yielded, on analysis, the following result : 0,256 gave 0,1404 Ag. Ag= 55.0. C7H,,0,Ag2 requires Ag = 55.4 per cent. Action of Ammonia on the Ethgl Esters (Middle Pi-action). The middle fraction of the ethyl ester obtained from the oxidation of isopilocarpine (p. 1334) was shaken with an equal volume of strong ammonia, and a crystalline amide obtained melting a t 151O. This was recrystallised many times from hot alcohol and from water, and a small quantity of an amide melting at 200' separated. As this proved to be identical with the amide obtained from the third fraction of the ester, it was set aside.The crystals from the mother liquors were recrystallised several times from alcohol and from water, and a pro- duct obtained melting a t 161°, but analysis showed that it was not pure, so that it was not possible to separate the homologous amides completely by this method, I n spite of all attempts to separate this middle fraction into its constituents, it could not be purified further than into two portions, one chiefly ethyl pilopate, and the other con- taining only a small quantity of this ester, Homopilopic Acid, C,H,,O,. The third fraction of the ethyl esters obtained by the oxidation of isopilocarpine (p.1334) gave, on analysis, results agreeing with those required for an ester of the formula C,,H,,O,. On treatment with ammonia, a crystalline arnide was obtained which melted at 1999 This amide, together with the portion melting a t 200' from the second fraction of the ester, was recrystallised from water and from hot alcohol until of constant melting point. It was readily crystallised from hot water, and separated in well-defined prisms melting sharply at 208' (corr.) On analysis : 0.168 gave 0.2938 CO, and 0.1246 H,O. 0.1172 ,, As in the case of the pilopic ester, the diamide of the hydroxy-acid C = 50.7 ; H = 8.7. 15 C.C. nitrogen at 20" and 769 mrri. N = 14.6. C8H160:$J2 rvquires C = 51 *1 ; H = 8% ; N = 14.9 per cent,. is formed in t h i s reaction.The mid, for which the name homopilopic acid is proposed, was obtained from the pure amide by heating with 20 per cent.hydro- chloric acid in a sealed tube at 120". The acid was extracted with ether, the ethereal solution washed with water, dried over calcium chloride, and distilled. The residual oil, after remaining in a vacuous desiccator over sulphuric acid for some days, showed no signs of crystallisation, and was therefore distilled in a vacuum. It boiled at 235-23'7" under 20 mm. pressure. On analysis : 0.141 gave 0.2864 CO, and 0.092 H,O. The acid is dextrorotatory, and a determinakion of its specific rota- C = 55.4 ; H= '7.2. C,H,,O, requires C = 55.8 ; H = 7.0 per cent. tion in aqueous solution gave the following result: a21" = + 1 * 6 O ; Z=l dcm.; ~=3*524; [u]F= +45*4O.With excess of alkali, the specific rotation is diminished : a:"= + 0 * 1 6 O ; Z = 1 dcm.; c = 2 . 8 2 ; [a]$"= +5*9'. The acid was titrated with decinormal alkali, using phenolphthalein as indicator, with the following results : 0.185 required in the cold, 10.5 C.C. for neutralisation, and, when boiled with excess of alkali and titrated back with acid, 21.4 C.C. ; this amount of a n acid, C,H,,O,, requires 10.75 C.C. and 21.5 C.C. respec- tively. The barium salts of the lactonic and hydroxy-acids were prepared in a manner similar to the corresponding salts of pilopic acid. The bavizcm salt of the luctonic ucid is a very hygroscopic powder, which, dried at 150°, yielded the following result on analysis : 0.1614 gave 0.079 BaSO,.The barium salt of the hydroxy-acid, which is microcrystalline and On Ba= 28.8. (CsH,,0,)2Ba requires Ba = 28.6 per cent. stable in the air, contains 1 mol. of water of crystallisation. analysis of the air-dried salt : 0.3542 gave 0.2414 BaSO,. 0.6094 at 150' lost 0.0314 H,O. H,O= 5.1. Ba = 40.1. C,H,,O,Ba,H,O requires Ba = 40.0 ; H,O = 5-3 per cent. Pinner and Kohlhammer's Piluvic Acid. It having been proved that pilopic acid has not the same formula as piliivic acid, the question arises whether homopilopic and piluvic acids may not be identical. Although it is not possible t o decide this ques- tion definitely, inasmuch as no physical constants have been recorded for piluvic acid by means of which i t may be identified, and as no proofI34 0 JOWETT : THE CONSTITUTION OF PILOCARPINE.PART 111. has yet been adduced that the acid and its derivatives were pure products, yet there are a number of facts which suggest the possibility of the identity of these acids, or, at any rate, that piluvic acid con- sisted largely of homopilopic acid. Forty grams of isopilocarpine were oxidised with 127 grams of per- manganate in the cold, and the ethyl ester isolated by the usiial method. On distillation under 20 mm. pressure, three fractions were obtained boiling at 160-1 70°, 170-1 90°, and 1 90-240° respectively. The lowest fraction, distilled under 760 rnm. pressure, gave a liquid boiling at 295", which was analysed with the following results : C=57*6 ; He7.3. 0.1996 gave 0.4126 CO, and 0*1308 H,O. C,H,,O, requires C = 58.1 ; H = 7.5 per cent.The liquid was therefore ethyl pilopate, so that, under the conditions of this oxidation, pilopic acid was formed. Experiments were made, using larger quantities of permanganate than previously employed, in order to obtain pilopic acid free from homopilopic acid, but this purpose was not accomplished, although the amount of volatile acids appeared to increase. It is more probable, therefore, that in the oxidation of isopilocarpine the molecule is attacked at two points, namely, a t contiguous carbon atoms, with the formation of pilopic and homopilopic acids, rather than that homopilopic acid is first produced and then oxidised to pilopic acid. It is of course possible that both factors come into play when a large excem of per- manganate is used.Pinner and Kohlhammer may therefore have been dealing with a mixture of pilopic and homopilopic acids, and their analytical results are in harmony with such a suggestion. Moreover, there is an experiment recorded by them which supports this view, namely, that in which an attempt was made to purify the amyl ester by distillation. In this case, the analytical results did not agree with any formula, and the authors admit the ester was impure; it was, however, prepared from the barium salt of the acid by a simple re- action, such as would lead to the formation of a product requiring ouly a single fractionation to obtain it in a state of purity. The fact that the ester was not pure throws doubt on the purity of the barium salt, although it is on the analysis of this salt, and of the acid derived from it, that the proof of the formula, C,H,,O,, given by Pinner and Kohl- hammer for piluvic acid is partly based.Experiments on the Constitution of Pilopic and Homopilopic Acids. For the purposes of these experiments, the syrupy acid was used, analysis having shown that only a small proportion of hornopilopic acid was present, Twenty-four gramv of ethyl pilopate mere treated withJOWETT : TEE CONST~TUTION OF PILOCARPINE. PART III. 1341 phosphorus pentabrornide, as already described (Trans., 1900, '7'7, 858), and 20 grams of an ester boiling at 180-190' under 10 mm. pressure obtained. This, when treated with diethylaniline, yielded 13 grams of a product which, when fractionated, first in a vacuum and then under the ordinary pressure, could be divided into two fractions: (1) 270--290°, a limpid oil; (2) 290-300°, a thicker oil, showing a tendency to deposit a waxy substance.The first fraction proved to be ethyl pilopate, and by hydrolysis the crystalline pilopic acid was obtained from it, On analysis of the ester : 0.0946 gave 0.2016 CO, and 0.0672 H,O. C = 58.1 ; H = 7.8. The second fraction, on analysis, yielded the following result : 0.1014 gave 0.2262 CO, and 0.0714 H,O. C = 60.8 ; H =5 7% It was not therefore the expected diethyl ester of the unsaturated acid. On hydrolysis, a syrupy acid was obtained which did not crys- tallise even when left in a vacuum over sulphuric acid a t 0' for several days. This acid yielded an amorphous silver salt containing 53.1 per cent. Ag (C7H80,Ag, requires Ag=58*1 per cent.), It was oxidised with permanganate at O', and an oily acid with a rancid odour was isolated from the products of the reaction.The silver salt prepared from this acid contained 51.4 per cent. Ag, but the quantity obtained was too small to purify, and as it was evident that this amount of acid did not represent the main reaction, the experiment was abandoned. Action of Hydriodic Acid on Pilopic Acid.-The acid was heated with three times its weight of fuming hydriodic acid in a reflux apparatus for several hours, but the pilopic acid was recovered unchanged. When heated in a sealed tube at 180°, no crystalline product was obtained, but only a small quantity of an oil having the odour of petroleum. A quantity of the acid was heated to 210' in a sulphuric acid bath, but no change took place, no gas or water being given off.C,H1404 requires C = 58.1 ; H = 7.5 per cent. C1,H,,04 requires C = 6 1 -7 ; H = 8.4 per cent. Fusion of Pilopic Acid with Potassium Hydroxide. Fusion at w High Tempevature.-Five grams of the syrupy acid were mixed with 25 grams of potassium hydroxide and a few drops of water, and the mixture fused for a short time. The fused mass was dissolved in water, acidified with sulphuric acid, and distilled with steam. The distillate, which had a rancid smell, was extracted with ether, the ethereal solution dried over colcium chloride, and distilled. VOL. LXXIX. 4 z1342 JOWETT : THE CONSTITUTION OF PILOCARPINE. PART in. The residue distilled completely at 110-1 60°, and the distillate was miscible with water.The barium salt was prepared and analysed : 0,2672 gave 0.2014 BaSO,. The calcium salt was also prepared, and obtained as white, pearly plates, which were dried on a porous tile, and, on analysis, yielded the following result : Ba = 44.3. (C4H702),Ba requires Ba = 44.1 per cent. 0.127, air-dried, lost 0'0112 H,O at 150'. (C4H7O2),Ca,H20 requires H20 = 7.8 per cent, Calcium isobutyrate crystalliaes with 4 mols. of water of crystallisa- tion, Further proof of the identity of this salt with calcium n-butyrate was afforded by making a saturated aqueous solution of the salt a t Oo, and placing the solution in warm water, when crystals separated which redissolved on cooling to O', The silver salt was prepared, and, after recrystallising once from hot water, furnished the following result on analysis : 0.136 gave 0.0752 Ag.C,H,O,Ag requires Ag = 55-4 per cent, H,O=8*8. Ag = 55.3. The volatile acid formed is therefore nm*maZ butyric acid. No other acid could be isolated from the residue left after distillation. Fusion at a Low Temperature.-Ten grams of acid were fused with 30 grams of potassium hydroxide and 5 C.C. of water, and kept gently simmering for some time. The fused mass was dissolved in water, acidified with sulphuric acid, and distilled with steam, but no volatile acid was obtained. The acid liquid was extracted with ether, the ethereal solution washed with water, dried over calcium chloride, and distilled. The residue weighed 6 grams, and on standing in a vacuum for some time, deposited a small quantity of crystals, which were separated, and drained on a porous tile.The non-crystalline residue was found to be unchanged pilopic acid. The residual liquid, after extraction with ether, was neutralised, evaporated to dryness, and extracted with alcohol. The alcohol was removed by distillation, the residue dissolved in a little water, and precipitated with lead acetate. The acid, regenerated from the lead salt by means of sulphuretted hydrogen, gave crystals mixed with unchanged pilopic acid, and when recrystallised from hot water came out in scales. When pure, it melted at 190' (con.), losing water, and forming, apparently, t h e anhydride, On analysis : 0.0258 gave 0.05 GO, and 0.016 H20. C=52.8 ; H=6*9. C,H,,O, requires C = 53.2 ; H = 6.3 per cent.JOWErT : TEE CONSTITOrION OF PILOCARPINE.PART 111. 1343 The acid was almost insoluble in ether, and sparingly soluble in cold water ; it decolorised permanganate solution. The silver salt was obtained as a granular precipitate on adding silver nitrate t o a solution of the ammonium salt of the acid. After washing, it was dried on a porous tile and analysed, with the follow* ing result : Ag=58.1 ; 0.116 gave 0.0674 Ag, 0.094 CO,, and 0,0238 H,O. C = 22.1 ; H = 2.3, C7H80,Ag, requires Ag = 58.1 ; C = 22.6 ; H = 2.1 per cent, Prom a consideration of the properties of this acid, i t would appear probable that it is an unsaturated acid closely allied to ethylitaconic acid, and that it is produced from the lactonic acid' by a similar reaction to that generally brought about by sodium ethoxide.By fusion at a low temperature, therefore, a small quantity of the isomeric unsaturated acid is formed, but the greater portion of the lactonic acid is recovered unchanged. Fusion of Honzopilopic Acid with Potassium Hydroxide and Tormation of a- Et~yltricurbullylic: Acid. A preliminary experiment having shown that a crystalline acid is formed by the fusion of homopilopic acid with potassium hydr- oxide at a moderate temperature, the whole of the syrupy homopilopic acid at disposal was fused with three times its weight of the alkali and a little water for half an hour ; the mass was then dissolved in water, acidified with sulphuric acid, and distilled with steam. Only a trace of a volatile acid was obtained. The acid liquid remaining after distillation was extracted with ether, the ethereal solution washed with water, dried over calcium chloride, distilled t o a low bulk, and then poured into excess of benzene.On standing, crystals separated, which were filtered off and dried on a porous tile. From the acid liquid, after extraction with ether, more acid can be obtained through the lead salt, as previously described. I n this way about 3 to 4 grams of a crystalline acid were obtained. This ucid melted indefinitely at about 117O, but after washing with hot benzene, fused a t 145". It was recrystallised from ether and from water until the melting point was constant, and was then obtained in hard prisms melting sharply at 157" (corr.). The acid is readily soluble in water or alcohol, and moderately so in ether; but on evaporating the ethereal solution an oil is obtained which gradually solidifies; it is insoluble in benzene or light petroleum.A 6 per cent. aqueous solu- tion was optically inactive. On analysis : 4 2 21344 JOWETT : THE CONSTITUTION OF PILOCARPINE. PART 111. 0.1338 gave 0.23 CO, and 0.073 H,O. C = 46.9 ; H = 6.1. 0.0922 ,, 0.159 CO, ,, 0.05 H20. C=47.0; H=6*0. C,H,,O6 requires C=47*1 ; H=5.9 per cent. The analytical results, melting point, and behaviour towards solvents agree with those recorded for a-et~yltricarballylic mid, and cz mixture of equal parts of the synthetical acid and that obtained by fusion melted at 1 5 7 O (corr.). Further evidence as to its identity with a-ethyltricarballylic acid was afforded by an examination of the followingderivatives, which agreed in all respects with those recorded in the following paper (p. 1346) for this acid.The anhydro-acid, prepared by heating the acid with excess of acetyl chloride in a reflux apparatus for 2 hours, could only be obtained as an oil soluble in benzene and yielding with aniline an amorphous compound. The silver salt was prepared by adding silver nitrate to an aqueous solution of the ammonium salt. The flocculent precipitate, insoluble in water, was well washed and dried, first on a porous tile, and then at 100'. On analysis : C = 17.8; 0-1248 gave 0.0816 CO,, 0.0246 H20, and 0.0768 Ag. 0.1354 gave 0.0836 Ag. C,H,O,Ag, requires C = 18.3 ; H = 1.7 ; Ag = 61.7 per cent. The calcium salt was prepared by digesting the aqueous solution of the acid with an excess of calcium carbonate and filtering.The filtrate, when heated to looo, became a firm jelly which liquefied on cooling. This behaviour has been shown to be very characteristic of calcium a-ethyltricarballylate. The solution of the calcium salt was evaporated to a low bulk in a vacuum and precipitated with alcohol. The precipitate was dried, first on a porous tile and then between blotting paper. On analysis, the air-dried salt furnished the following results : 0.1284 a t 150' lost 0.0306 H20, and on ignition gave 0,031 CaO. H=2.2; Ag=61.6. Ag = 61 -7. H,O = 23.8 ; Crt = 17.3. (C,H,06),Ca,,9H,0 requires H,O = 23.7 ; Ca = 17.5 per cent. The copper salt, prepared in the usual way with copper acetate, was R bluish-green precipitate insoluble in bot water.After drying on a porous tile and then at 120°, it furnished the following results on analysis : 0.0636 gave 0.0256 CuO. Cu = 32.1. (C,H,O,),Cu, requires Cu = 32.2 per cent.JOWETT : THE CONSTITUTION OF PILOCARPINE. PART 111. 1345 Constitutional Formulm of Pilopic and Homopilopic Acids. The identification of a-ethyltricarhallylic acid as a product of the fusion of homopilopic acid with potassium hydroxide, and the other facts recorded in this paper, render it possible to state with a high degree of probability the constitutional formulae of both pilopic and homo- pilopic acids. The formation of acetic and propionic acids by the oxidation of isopilocarpine and of normal butyric acid by the fusion of pilopic acid with potassium hydroxide, prove that the isobutyl group does not exist in isopilocarpine, and that the formation of SO- butyric acid by the fusion of the alkaloid with potassium hydroxide is probably due t o the action of the fused alkali on the normal acid first formed.That isopilocarpine must contain the n-butyl grouping follows from the formation of a-ethyltricarballylic acid, C,H5 CH( CO,H)*CH( C0,H) *CH,*CO,H. The formation of the tricarboxylic acid from the hydroxydicarb- oxylic acid (as potassium salt) can only be explained on the assumption that the CH,*OH group is oxidised to C0,H. The ethyltricarballylic acid may therefore be derived from one of the three following hydroxy- dibasic acids : 2 H5* yH-FH*CH,*CO,H : C,H,*~H-QH*CH,*CO,H : CK,*OH CO,H CO,H CH,-OH C,H,-Q H-FH*CH,*CH,*OH C0,H C0,H On account of the stability of homopilopic acid, it is most reasonable From the above formulae, four to assume that it is a y-lactonic acid, y-lactonic acids may be derived : (1).(2). C,H,*~H-~H*CH,*CO,H : C,H,*~H-$'H*CH,*CO,H CH,*O*CO co 0. CH, (3). C,H,*FH-FH--FH, . . C,H,*S)R---FH-QH, C0,H CH,*O*CO GO,€€ CO*O*CH, If we regard pilopic acid as derived from homopilopic acid by the loss of carbon dioxide and pxidation of the contiguous carbon atom, only formulae (1) and (2) are possible, as (3) and (4) would yield acids containing less than seven carbon atoms. The formation of pilopic acid during the oxidation of isopilocarpine may be assumed t o be due either to oxidation of the homopilopic acid first formed, or, as has been previously pointed out, to simultaneous1346 JOWETT: A NEW SYNTHESIS OF oxidation at two different points in the molecule. Since, however, both acids contain the n-butyl group, i t is most probable that they bear the relation to each other previously suggested, since oxidation must have occurred at that portion of the molecule containing the nitrogen atoms. I f this argument be admitted, the possible formulae for pilopic acid will be, (1). (2). C,H,*YH---QH*CO,H or C,H, YH-YH*CO,H but of these (1) is clearly not admissible as it is a malonic acid derivative and should therefore lose carbon dioxide on heating a t 200°, which, as has been shown, is not the case. There remains therefore for pilopic acid the second formula, and the corresponding formula for homopilopic acid is C2H5* VH-$IH*CH,-CO,H CH,*O* CO CO*O* CH, , GO * o* CR, Lactonic acids corresponding to these formulae have not hitherto been prepared, but pilopic acid resembles ethylparaconic acid in many of its physical properties, and the relation between the two is shown by their formulae: C,H,*QH-~H=CO,H : C,H,*QH~H*CO,II CO*O*CR, O*CO* CH, Pilopic acid. Ethylparaconic acid. It remains, therefore, to synthesise acids having the constitution assigned to pilopic and homopilopic acids, and to contrast the properties of the acids prepared synthetically with those recorded in this paper. Experiments with this end in view are now in progress. THE WELLCOME CHEMICAL RESEARCH LABORATORIES.

ISSN:0368-1645    

DOI:10.1039/CT9017901331

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

1346 JOWETT: A NEW SYNTHESIS OF CXLI1.-A New Synthesis of a-Ethyltricccrballylic Acid. By HOOPER ALBERT DICKINSON JOWETT. IN the preceding paper, it was shown that by the fusion of homo- pilopic acid with potassium hydroxide an acid of the formula C,H,,O, was formed and that the properties of this acid corresponded with those of a-ethyltricarballylic acid. As, however, two different melting points have been assigned to this acid and as no derivatives have been described other than the silver salt, it was necessary to prepare theU-ETHYLTRICARBALLYLIC ACID, 1347 substance and to examine it more fully, so as to be able to identify completely the acid formed from homopilopic acid with the synthetical compound. a-Ethyltricarballylic acid was first prepared by Auwers (Ber., 1891, 24, 307, 2897) by the condensation of ethyl ethylsodiomalonate with ethyl f umarate and subsequent hydrolysis.The acid, after recrystal- sation, melted a t 147-148' and was readily soluble in water, but only moderately so in ether ; on evaporation, the ethereal solution left a n oil which became crystalline. The substance was prepared more recently by Michael (Ber., 1900, 33, 3745) by the same method, but he found that after further purification it melted at 155-15'7'. I n order to prepare the acid for the purpose of comparison, i t was deemed advisable t o accomplish the synthesis by an entirely different method, as this a t the same time would afford additional proof of the correctness of the constitution of the synthetical acid prepared by Auwers.Ethyl ac~lccno-p-et~ylsuccina,te was prepared by the general method of preparation of the alkyl-substituted succinic acids described by Bone and Sprankling (Trans., 1899, 75, 839), by condensing the sodium compound of ethyl cyanoacetate with ethyl a-bromobutyrate. The sodium compound of ethyl a-cyano-P-ethylsuccinate was then condensed with ethyl bromoacetate with the formation of ethyl P-cyano-a-ethyltricarballylate. This stage of the synthesis may be presented by the following equation : CHzBr *CO,Et + C0,Et * CNa( CN)* CH( C,H,).CO,Et = C0,Et * CH,*C( CN)( CO,E t) *CH(C,€I,) C0,Et + NaBr. The ethyl cyanoethyltricarballylate, on bydrolysis, yielded an acid from which carbon dioxide was eliminated by heating at 180" with the formation of a-ethylcarballylic acid.These condensations took place readily, the yield of cyano-esters in the first and second stages of the synthesis being 50 and 70 per cent. respectively of the calculated amounts. As these cyano-esters have not been previously prepared, their boiling points and densities were determined. a-Ethyltricarballylic acid as thus prepared was found to agree in its general properties with those previously recorded, and after recrystal- lisation melted a t 157' (corr.), thus confirming the figure given by Michael. Of its derivatives described later, the calcium salt is very characteristic ; it is fairly soluble in cold water, but on warming the aqueous solution, the liquid is converted into a solid jelly, which liquefies on cooling. This gelatinisation of the calcium salt, coupled with the melting point of the acid, affords the best means of identifying the substance.1348 JOWETT: A NEW SYNTHESIS OF EXPERIMENTAL.Ethyl a-Cyano-P-cthylsuccinate, CO,Et .CH( CN)*CH(C,H,) C0,Et. This ester was prepared as follows :-28*5 grams of ethyl cyano- acetate were mixed with a solution of 5.75 grams of sodium in 70 grams of absolute alcohol, and to the resulting thick paste 48.75 grams of ethyl a-bromobutyrate were added. The mixture, which became warin, was heated on a water-bath until neutral, which generally required 2-3 hours; it was then cooled, poured into water, and the oil which separated was extracted with ether. The ethereal solution was washed with water, dried over calcium chloride, and then distilled. The residual oil was fractionated under 20 mm.pressure, when a quantity of uncbanged ethyl cyanoacetate and ethyl a-bromobutyrate distilled below looo, but the greater portion of the liquid distilled a t 160-1 70°, leaving only a very small residue in the flask. On refractionation, the portion distilling a t 160--170° waii collected, Of this a portion boiling constantly at 167-16S0 was set aside for analysis; it had a density d 15*/15O = 1.0647. The yield of product boiling at 160-170° under 20 mm. pressure was 50 per cent. of the theoretical. On analysis : 0.1338 gave 0.285 CO, and 0.0916 H,O. C = 58.1 ; H = 7.6. 0.1512 ?, 9.4 C.C. nitrogen at 24' and 764 mm. N = 6.8. C,,H170,N requires C = 58.1 ; H = 7.5 ; N = 6.2 per cent. The correctness of the formula ascribed to the cyano-ester was proved by the fact that on hydrolysis the compound furnished ethylsuccinic acid melting at 98", which on analysis yielded the following result : 0.132 gave 0.2372 CO, and 0.086 H,O.C-49.0 ; H17.2. C,H,,O, requires C = 49.3 ; H = 6.9 per cent. The characteristic calcium ethylsuccinate was also prepared. Ethyl p-Cyano-a-ethyltricarballyhte, C0,Et *CH( C,H,)* C( CN)( C0,Et) *CH2*C0,Et. This cyano-ester was prepared as follows:-To 6 grams of sodium dissolved in 60 grams of absolute alcohol, 45.4 grams of ethyl-a-cyano- P-ethylsuccinate were added. The mixture became warm and very viscid, but no solid separated ; after cooling, 33.4 grams of ethyl bromo- acetate were added, when areaction at once took place with evolution of heat and separation of sodium bromide.The mixture mas heated for half-an-hour on a water-bath, cooled, and then poured into water. The oil which separated was extracted with ether, the ethereal solution washed with water, dried with calcium chloride, and distilled. The residual oil was carefully fractionated under 20 mm. pressure. ScarcelyU-ETHYLTRICARBALLYLIC ACID. 1349 any liquid distilled below 195O, the greater portion came over between 195" and 215O, leaving a small residue in the flask. On refractionation, the portion distilling at 205-208' under 17-21 mm. pressure was collected, the greater portion, boiling constantly a t 208" under 21 mm. pressure, being put aside for analysis and for the determination of its density. The yield of refractionated product was 70 per cent. of the theoretical.On analysis : 0.1716 gave 0.3602 CO, and 0,1144 B,O. 0.1756 ,, 7.5 C.C. nitrogen a t 24" and '764 mm. N = 4.7. C = 57.3 ; H= 7.4. U,,H,,O,N requires C = 57.5 ; H = 7.3 ; N = 4.5 per cent. The density a t 16" compared with water a t 16" was 1.0972. a-Et~yZtricarbaZZyZic Acid, CO,H*CH( C,H,) * CH(CO,H)* CH,*CO,H. This acid was obtained from the ethyl cyanoethyltricarballylste in the following manner. The ester was first boiled with five times its weight of 40 per cent. aqueous sulphuric acid in a reflux apparatus until all the oily drops had disappeared, which generally required a period of 24-48 ~IOUL'S. The acid liquid was then saturated with ammonium sulphate and extracted with ether six times. The ethereal extract was distilled to a convenient bulk and extracted with dilute sodium carbonate solution.This was acidified with sulphuric acid, saturated with ammonium sulphate, and extracted with ether. The ethereal solution was washed with water, dried with calcium chloride, distilled to a low bulk, and then poured into ten times its volume of benzene. On standing, crystals separated which were filtered off ; these, when dried, melted a t 117" with effervescence. The acid was then heated in a small flask in a paraffin bath a t 180" until all evolution of gas had ceased. After cooling, the mass mas dissolved in a little hot water, boiled with animal charcoal, and filtered. On standing and stirring with a glass rod, the solution became pasty. The crystals were drained on a porous tile and recrystallised from a little water until of constant melting point; thus purified, they melted a t 156-15'7O (corr.).The pure acid required about 20 times its weight of ether to dissolve it, but on evaporating this solution at the ordinary temperature, no crystals separated until all the ether had evaporated, when an oil was left which gradually became solid. On analysis : 0.1974 gave 0.341 CO, and 0-106 H,O. C = 47.1 ; H = 6.0. 0*198 ,, 0.342 CO, ,, 0.1064 H,O. C=47*1 ; H=6*0. C,HI20, requires C = 47.1 ; H = 5.9 per cent. The anhydro-acid was prepared by adding the acid to three times its weight of acetyl chloride and boiling for 2 hours in a reflux apparatus. The acid slowly dissolved and the excess of acetyl chloride was removed1350 A NEW SYNTHESIS OF ~-ETHYLTRICABBALLYLIC ACID. by evaporation desiccator over varnish was ob on the water-bath and subsequent standing in a vacuous solid potassium hydroxide.I n this way, a hard, sticky ltained, which could not be crystallised. On analysis : 0.2218 gave 0.4146 CO, and 0.1108 H,O. The anhydro-acid dissolved in benzene ; on the addition OF aniline to the solution, heat was developed, the liquid immediately became cloudy, and an amorphous precipitate separated which, however, could not be obtained crystalline. The barium salt was prepared by digesting an aqueous solution of the acid with excess of barium carbonate until neutral, and filtering. On warming the filtrate, crystals appeared which, however, redis- solved on cooling, The filtrate was evaporated to a small bulk, filtered while hot, and the crystals dried, first on a porous tile and finally between blotting paper.Analysis showed that the air-dried crystals contained 7 mols. of water of crystallisation, of which six are removed by heating at 180° : C=51-0; H=5*5. C,H,,O, requires C = 51.6 ; H = 5.4 per cent. 0-3156 at 180" lost 0.036 H,O and gave 0.234 BaSO,. 0.1716 gave on combustion 0,0526 H,O. H20 = 11.4 ; Ba = 43.6. H = 3.4. (C8H,06)2Ba,,7H20 requires H20= 13.4 ; Ba= 43.8 ; H= 3.4 per cent. The culcium salt was prepared by digesting an aqueous solution of the acid with excess of calcium carbonate and filtering. The filtrate had the remarkable property of becoming a firm jelly when heated to looo, and liquefying on cooling. The liquid was evaporatedeto a small bulk in a vacuum and the calcium salt precipitated with alcohol in a micro;crystalline form.On analysis : 0,1886 at 150" lost 0.044 H20 and on ignition gave 0.0454 CaO. H,O = 23.3 ; Ca = 17.2. (C8H,06),Ca,,9H,0 requires H20 = 23.7 ; Ca = 1 7 5 per cent. The copper salt, prepared by adding copper acetate solution to an aqueous solution of the ammonium salt of the acid and boiling, was a greenish-blue, flocculent precipitate. 0.1972 at 150° lost 0-0372 H20 and on ignition gave 0.0696 CuO, On analysis : H20 = 13.8 ; CU = 28.2. (C,H,06)2Cu,,5H,0 requires H,O = 13.2 ; Cu = 28.0 per cent. The triethyl ester, prepared in the usual manner by the action of sulphuric acid and ethyl alcohol on the acid, was a limpid, colourless liquid boiling at 170-175" under 16 mm. pressure. On analysis, it furnished the following results :BENZOYLATION OF ACIDS IN PRESENCE OF AMMONIA. 1351 0.2136 gave 0.457 CO, and 0.1574 H20. An attempt t o prepare the amide by mixing the ester with excess of C = 58.3 ; H = 8.2. C14H2406 requires C = 58.3 ; H = 8.3 per cent. strong ammonia was unsuccessful, Addendum-Since this paper was in type the author has received a communication from Dr. Bone pointing out the following passage in a paper, Researches on the Alkyl Substituted Succinic Acids,” by Bone and Sprankling (Trans., 1899, 75, 864) : “Finally, we are studying the interaction of the sodium derivative of ethylic cyanosuccinates and the ethylic salts of a-bromo-fatty acids.” As the purpose for which reference was made to the paper in ques- tion only necessitated the reading of that portion of it relating to the details-of preparation of the analogous ethyl cyanomethylsuccinate, the concluding paragraph containing the passage referred to most unfortunately escaped my attention, The necessity for the preparation of a-et hyltricarballylic acid and certain of its derivatives was due to the great importance of identify- ing beyond question the acid formed by the fusion of homopilopic acid with potassium hydroxide. THE WELLCOME CHEMICAL RESEARCH LABORATORIES.

ISSN:0368-1645    

DOI:10.1039/CT9017901346

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

BENZOYLATION OF ACIDS IN PRESENCE OF AMMONIA. 1351 CXLIIL-BenzoyZation o f Fatty Acids in the Presence o f Ammonia. Formation of Arnides. By K. J. P. ORTON. IT was recently shown (Orton and Garrod, J. Physiol., 1901, 2'7, 89) that p-dibenzoxyphenylacetamide was formed in the benzoylation, by the Schotten-Baumann method, of an abnormal urine, the so-called '' alcapton -urine," which contains p-dihydrox y phen ylacetic acid (homo- gentisic acid), and it was further demonstrated that the production of this amide depended on the presence of ammonia in the urine. Investigation has proved that many acids under similar condi- tions yield an amide. Thus, from stearic, phenylacetic, p-nitro- phenylacetic, and cinnamic acids, amides are formed, whilst p-aminophenylacetic, p-h ydroxyphenylacetic, and mandelic acids are both benzoylated and converted into amides. Tyrosine yields di- benzoyltyrosinamide.Aromatic acids, for example, benzoic and toluic acids, do not yield amides. If, instead of ammonia, an aqueous solution of methylamine is used, the corresponding methyl- arnicles are obtained,1352 ORTON: BENZOYLATION OF FATTY ACIDS IN THE The benzoylation was carried out in the following way. To a dilute ammoniacnl solution of the acid (1 part) is added excess of benzoyl chloride (2-3 parts); a 10 per cent. solution of sodium hydroxide is introduced in successive portions, and the mixture well shaken until the smell of benzoyl chloride is no longer perceptible. As the benzoyl chloride disappears, a solid separates, which is a mixture of benzamide and the amide of the acid.The quantity of the former is but small, when only sufficient ammonia to dissolve the acid has been used; excess of ammonia increaaes the proportion of benzamide. The yield of amide (or methylamide) is generally small and does not exceed 25 per cent. of the calculated amount except in one or two cases. If the acid and benzoyl chloride are heated together for 2 or 3 hours at 100-120° and the mixture then treated with a solution of sodium hydroxide and ammonia (or methylamine), the yield is much increased, and frequently amounts to 75 per cent. of the acid used. One or two explanations of the above reaction suggest themselves. It may be supposed that an anhydride is first formed, either a com- pound anhydride of benzoic acid and the fatty acid, or a simple anhydride of the fatty acid ; thus : C,H,*COCl + R*CO.OH = C,H,*CO*O*CO*R + HCl or BR*CO*OH + C6H50COC1 = (R*CO),O + C,H,*CO*OH + HCl.On the other hand, the benzoyl chloride may interact with the acid, forming benzoic acid and the chloride of the acid, thus: C,H,*COCl + R*CO*OH = C,H,*CO*OH + R*COCl. Bauer (Inazlg. Dissert. Tiihingen,, 1901) records the fact that benzoic anhydride is formed when benzoyl chloride is shaken with a solntion of sodium hydrogen carbonate. I n a patent of Knoll & Go. (D.R.-P. 117267), the production of compound anhydrides from acid chlorides and acids i n the presence of alkali carbonates is mentioned. Further, according t o BQhal (Compt. rend., 1899, 129, 681), acetic benzoic anhydride yields acetamide and benzoic acid with ammonia.From these facts, it seems probable that a compound anhydride of benzoic and the fatty acid (or possibly a simple anhydride of the fatty acid) is formed when the acid is treated with benzoyl chloride in presence of sodium hydroxide, and that this anhydride reacts with ammonia, pro- ducing benzoic acid and the amide of the fatty acid. When the fatty acid is heated with benzoyl chloride, the chloride of the fatty acid may be formed, and in support of this view, Pol- zenius (Chem. Zeit., 1896, 20, 46) has observed that benzoyl chloride and acetic acid at llOo yield benzoic acid and acetyl chloride. With pbenylacetic and rnandelic acids, a t least, this does not appear toPRESENCE OF AMMONIA. FORMATION OF AMIDES. 1353 be the case.Molecular proportions of phenylacetic acid and benzoyl chloride (19 grams of each) were heated together for about 2 hours a t 120' and for a short time a t 150'. As soon as the hydrogen chloride, which was a t first rapidly evolved, ceased to be given off, the mixture was distilled under 28 mm. pressure in order t o isolate phenylacetyl chloride (b. p. 102.5' under 17 mm.) ; 2.5 grams of an oil passed over a t 110-140°, and appeared to be chiefly benzoyl chloride and to contain little, if any, phenylacetyl chloride." The residue in the flask, which was nearly free from acid chloride, did not solidify on cooling and could not be crystallised from any solvent. After 2 or 3 days, crystals of benzoic acid began t o separate. When the oil is boiled with water, benzoic and phenyl- acetic acids are formed.With ammoniaj the oil reacted with develop- ment of heat and immediately solidified, The solid was nearly pure phenylacetamide (m. p. 152"), and on acidifying the ammoniacal mother liquor, benzoic acid separated. Aniline similarly . yielded phenylacetanilide (m. p. 117") and benzoic acid ; no trace of benz- anilide was discovered. From this experiment, it would seem probable that an unstable compound anhydride is also the main product when the acid chloride and acid are heated together. Further experiments on the preparation and reactions of these compound anhydrides are in progress. p-i%trophenylacetmethylarnide, NO,* C,H,* OH,* CO *NH* CH,.-pNi- trophenylacetic acid (1 gram) was heated with benzoyl chloride (2 grams) on the water-bath for 2 hours, A little water was poured on the oil, and 3 C.C.of a 33 per cent. aqueous solution of methylamine added. The mixture was then shaken with a 10 per cent. aqueous solution of sodium hydroxide, introduced in successive portions, until the odour of benzoyl chloride had disappeared. The solid remaining was collected, washed with water, and recrystallised from boiling water. The methylamide crystallises in long, silky, colourless needles melting at 159', and is very soluble in all solvents, except water and petroleum. It is slowly hydrolysed by boiling aqueous sodium hydr- oxide, but rapidly by an alcoholic solution, with evolution of methyl- amine. 0.1472 gave 19 C.C. moist nitrogen at 23' and 765 mm. p-Benzoylccrninophenghcetamide, C,H,* CO *NH* ,H4* CH,* CO *NH,.-This amide is readily formed when p-aminophenylacetic acid is benzoylated by the Schotten-Baiimann method in the presence of ammonia. Two grams of the acid were dissolved in 20 C.C. of 10 per * The boiling points of these acid chlorides lie very near together. N = 14.51. C9Hlo0,N2 requires N = 14.43 per cent.1354 ORTON: BENZOYLATION OF FATTY AClDS IN THE cent. ammonia ; to the solution was added excess of benzoyl chloride ( 5 c.c.), and the mixture then shaken with sodium hydroxide. The solid was collected, washed with water, and recrystallised from alcohol. The amide crystallises in small plates melting at 248O, and only slightly soluble in all solvents, One gram of the pure amide was obtained ; the yield is not increased when the acid and benzoyl chloride are heated before treatment with ammonia and sodium hydroxide.0.1048 gave 0.2716 GO, and 0.0533 H,O. 0.1103 ,, 10.8 C.C. moist nitrogen a t 20Oand 771 mm. N = 11.30. C = 70.68 ; H = 5.65, C1,H1,0,N2 requires C = 70.86 ; H = 5.51 ; N = 11 -02 per cent. On hydrolysing the amide with alkalis or acids, p-aminophenylacetic and benzoic acids were always formed. p-Benzoytaminop~nyZacetic Acid, C,H,* CO *NR* C,H,* CH,* CO,H, is formed when paminophenylacetic acid is benzoylated by the Schotten-Baumann method. The clear alkaline solution, obtained when all the benzoyl chloride has disappeared, was acidified with acetic acid. The solid which separated was dissolved in alcohol, and crystallised therefrom in tufts of needles melting at 205-206'.0,1424 gave 7.1 C.C. moist nitrogen at 1 9 O and 767 mm. p-Benxoxyphenylacetamide, C,H,* CO*O*C,H4- CH2* CO *NH,, is best prepared by heating p-hydroxyphenylacetic acid and benzoyl chloride before treatment with ammonia and sodium hydroxide. The solid was washed with ether and then recrystallised three or four times from alcohol, in which it is only slightly soluble. It forms microscopic crystals which melt at 167-169'. N=5*78. Cl5H,,O3N requires N = 5.48 per cent. 0-1808 gave 8.1 C.C. moist nitrogen a t 16O and 763 mm, N = 5-34. C,,Hl3O,N requires N = 5.48 per cent. Sufficient material for the preparation of p-benzoxyphenylacetic acid Benzoylrnandelarnide ~heltyl~nxoylg~ycolEamide), was not available. C6H,*CH(O*CO*CBH,)=CO*NH2, is easily prepared from the calculated amount of mandelic acid and t o the extent of about 75 per cent. when the acid and benzoyl chloride are heated together at 120°, before the addition of ammonia and sodium hydroxide.After the benzoyl chloride has disappeared, a sticky semi- solid mass remains, which after washing with ether becomes a white, crystalline solid. On recrystallisation from water or dilute alcohol, the amide is obtained pure in tufts of silky needles melting a t 162', and readily soluble in alcohol, chloroform, or benzene, but only slightly so in petroleum, cold water, or ether,PRESENCE OF AMMONIA. FORMATION OF AMIDES. 1355 0.1996 gave 10 C.C. moist nitrogen at 21' and 765 mm. N= 5.71. C,,H130,N requires N = 5-48 per cent. Benxoylmundelmethylarnide, C,K,* CH(O*CO* C6H5) *GO* NH*CH,, is prepared and purified exactly as the amide, methylamine replacing ammonia.It crystallises from dilute alcohol or water in tufts of needles melting a t 139'. 0.1970 gave 9.4 C.C. moist nitrogen a t 18' and 760 rnm, N = 5.48. C16H150,N requires N = 5.2 per cent. All attempts t o obtain benzoylmandelic acid from the amide failed, Aqueous hydrochloric acid attacks it very slowly, whilst the alcoholic acid converts it rapidly into ethyl benzoate and mandelate. Seventy- five per cent. nitric acid containing nitrous acid-the reagent which so satisfactorily converted dibenzoxyphenylacetamide into dibenzoxy- phenylacetic acid (loc. cit.) -produces only benzoic acid. Alkalis bring about complete hydrolysis. Mandelic acid could not be benzoylated by the Schotten-Baumann method with sodium hydroxide or sodium hydrogen carbonate, or by use of pyridine in the manner recommended by Einhorn and Hollandt (Annulen, 1898, 301, 95).On heating mandelic acid with benzoyl chloride at l l O o , a n oil is ob- tained which decomposes with water or alkalis, but with ammonia gives benzoylmandelamide. Cinnamic Methylamide, (I,H5*CH:CH*C0.NH*CH3, is obtained, in the manner previously described, as a pasty mass, which solidifies on cooling with ice. It crystallises from hot water in plates melting a t 111', and is very soluble in all solvents, except water and petroleum. 0.1856 gave 14.9 C.C. moist nitrogen at 25' and 764 mm. CloHllON requires N = 8.7 per cent. Dibromocinnarnic Methylamide, C,H5*CHBr*CHBr*CO'NH*CH3.-- To a solution of cinnamic mefhylamide (1 mol.) in chloroform, a solution of bromine (1 mol.) in the same solvent was slowly added.The colour of the bromine rapidly disappeared and crystals separated ; these were dissolved in alcohol, from which they crystallised in lustrous, colourless prisms. On heating, the dibromo-compound becomes coloured at 200°, and melts and decomposes at 214'. N = 8.9. 0.1456 gave 0.1700 AgBr. Dibenxo yltyyosinanzide, Br = 49.67. CloHl,ONBr, requires Br = 49.84 per cent, C,H,*CO*O 'C6H;CH2*CH(NH *COeC6H,)'CO'NH2. -One gram of tyrosine was dissolved in 10 C.C. of a 10 per cent. solu- tion of ammonia and 2 C.C. of benzoyl chloride were added, After1,356 FRANKLAND AND FARMER : shaking with caustic soda until the benzoyl chloride had disappeared, the solid was filtered and washed with water and then with ether. The amide crystallises from dilute alcohol in nests of small, lustrous needles melting a t 246", and is moderately soluble in. alcohol ori chloroform. It is decomposed only slowly with evolution of ammonia by boiling concentrated alkali hydroxides ; in the presence of alcohol, the action is more rapid and tyrosine and benzoic acid are formed besides ammonia. 0.107 gave 0.278 CO, and 0.0445 H,O. C = 70.86 ; H = 4.62. 0.0962 ,, 6.0 C.C. moist nitrogen at 2 0 5 O and 754 urn. C,,H,,O,N, requires C = 71.1 ; H = 5.1 ; N = 7.2 per cent. Steai*amide, C,7H,,*CO'NH,, was first prepared by Carlet (Jahresbm., 1859, 367) from ethyl stearate and ammonia. It can be very easily obtained by heating stearic acid and benzoyl chloride a t 110-120' and subsequently treating the mixture with ammonia and sodium hydroxide. Prom chloroform, it crystallises in nests of needles melting a t 106-107°. N = 7.3. This reaction has been tried with many other acids, Dicarboxylic. aliphatic acids appear not to yield an amide, or at least only in very small quantities. From sulphonic acids, derivatives are obtained, but so far only in small amount. ST. BARTHOLOMEW'S HOSPITAL AND COLLEGE, E. c.

ISSN:0368-1645    

DOI:10.1039/CT9017901351

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

1,356 FRANKLAND AND FARMER : CXLIV.--Liquid Nitrogen Peroxide as cc Solvent. By PE;RCY PARADAY FRANKLAND, Ph.D., F. H.S., and ROBERT CROSBIE FARMER, M.Sc. (Vict.), Ph.D. THE object of the following investigation was to ascertain more accurately than has hitherto been attempted the properties of lique- fied nitrogen peroxide as a solvent; in particular to determine to what extent organic compounds can be dissolved in it without de- composition and in the cases where they are attacked to ascertain the nature of the reaction. The question presented itself, whether substances dissolved in lique- fied nitrogen peroxide exist in the normal state of molecular aggregation or whether they undergo electrolytic dissociation on the one hand, or associate themselves to complex inolecules on the other.As it boils at 21", it can be readily condensed in an ordinary freezing Nitrogen peroxide is a comparatively easily liquefiable gas.LIQUID NITROGEN PEROXIDE AS A SOLVENT. 1357 mixture. It can therefore be easily purified by redistillation and can be boiled for many hours in an ebullioscopic apparatus without any serious loss, if the vapour be condensed by means of a freezing mixture Its reactions and properties can be examined with ease at a temper- ature a little below Oo, and the pure solvent may be recovered from its solutions by distillation. The chief difficulty met with in working with this solvent was the extreme rapidity with which it attacks india-rubber and cork. This rendered it necessary to use glass connections in almost all cases, since rubber and cork were destroyed in a very short time, even when protected as well as possible by a coat of vaseline or paraffin wax.In some cases, connections could be made with asbestos paper coated with vaseline. A review of the literature on the subject of liquid nitrogen peroxide reveals very little work on the solvent powers of this substance. The chemical activity of nitric acid, when brought in contact with organic compounds, seems to have led to the belief that nitrogen peroxide would be still more active, and that very few organic compounds would be able to withstand its action. Thus Ramsay (Trans., 1890, 57, 592),inhiswork on the depression of the freezing point of nitrogen peroxide by dissolved substances, mentions chloroform and chloro- benzene as being ‘( among the few available and unobjectionable substances which are not acted on by nitrogen peroxide.” We have, therefore, been somewhat surprised to find that liquid nitrogen peroxide is not only a remarkably good solvent for most organic compounds, but also a comparatively inert substance in the pure anhydrous condition.It is probable that many previous workers have made their observations with slightly impure nitrogen peroxide, and this would account for their statements to the effect that it attacks most organic compounds, for it has also been our experience that although the pure nitrogen peroxide is comparatively inert, yet the slightly impure product, that is, a product which has not been completely dehydrated or which contains traces of lower oxides, is much more active and frequently attacks compounds which are unaffected by the pure peroxide ; thus cane sugar was soluble without decomposition in the pure solvent but was very quickly attacked when the nitrogen peroxide contained traces of water.In its general behaviour, liquid nitrogen peroxide shows a con siderable resemblance to the common organic solvents, Inorganic salts were found to be quite insoluble in it, whereas most organic compounds dissolved with at least the same ease as in ether. As will be seen later, many of these were unacted on, although in some cases nitration, oxidation, &c., set in. VOL. LXXIX. 5 A1358 FRANKLAND AND FARMER : It was thus possible, in the case of many organic compounds, to examine the solutions as regards electric conductivity, and further to determine the molecular weights of a number of compounds by the rise of boiling point.The electric conductivity of the solutions was measured in order to ascertain whether ionic dissociation occurs to any appreciable extent when substances are dissolved in nitrogen peroxide. Recent researches have shown that a number of hitherto unsuspected liquids act as '' ionising solvents." In particular, the interesting researches of Walden on liquefied sulphur dioxide (Ber., 1899, 32, 2862), and of Franklin and Kraus on liquefied ammonia (Amer. Chem. J., 1899, 23, 277 ; 1900, 24, 83) have shown that these liquids dissociate dis- solved substances to a considerable extent. Many other cases of ionising solvents have also come to light in recent years (compare Amer. Chem.J., 1901,25, 232). The probability that liquefied nitrogen peroxide would also prove t o be an ionising solvent formed the original inducement to the following investigation, and the fact that Bouty (Compt. rend., 1888, 106, 595) found solutions in pure nitric acid to be good conductors of electricity seemed to justify this expectation. When it was found, however, that liquid nitrogen peroxide did not dissolve inorganic salts, whereas it readily dissolved indifferent organic compounds, it seemed more probable that it resembled such organic solvents as benzene in its behaviour. The electric conductivity of nitrogen peroxide itself has already been measured by Boguski (Zeit. physikal. Chena. 1890, 5, 69), who found that the pure peroxide is a non-conductor, but that when a little water is added the electric conductivity increases enormously. No experiments appear to have been made with solutions in liquid nitrogen peroxide, We find the solutions in the liquid nitrogen peroxide to be to all intents and purposes absolute non-conductors.The dissolved sub- stances do not, therefore, exist to any appreciable extent in the ionised state. On the contrary, as will be shown, many compounds are asso- ciated to complex molecules when dissolved in this liquid. The experiments were all carried out with acids, bases being attacked immediately and salts being insoluble, I n every case, it was found that the solutions conducted just as little as the pure solvent. It may therefore be safely concluded that liquid nitrogen peroxide is not an ionising solvent.In order to examine the state of molecular aggregation of substances dissolved in this liquid more fully, we have made a number of molecular weight determinations by observing the influence on the boiling point of the substances dissolved. The constant was first ascertained by means of a series of experiments in which solutions of indifferent This has been borne out by experiment.LIQUID NITROGEN PEROXIDE AS A SOLVENT. I359 organic compounds were employed. Various acids were then examined and in many cases these were found to be associated to double molscnles. Nitrogen peroxide therefore resembles benzene and some other organic liquids in its power of associating many dissolved hydroxy-compounds.This is, we believe, the first case in which an inorganic solvent has been found to bring about an association of dissolved substances. EXPERIMENTAL. For the preparation of liquid nitrogen peroxide, the method described by Cundall (Trans,, 1891, 59, 1077) was found to be the most satis- factory. The method of heating dry lead nitrate was at first employed, as it gives a very pure product. The yield is, however, only moderately satisfactory, and moreover, the tube in which the lead nitrate is heated occasionally becomes stopped up and necessitates breaking off the experiment, The method described by Cundall, in which arsenic trioxide is heated with a mixture of sulphuric acid and fuming nitric acid, gives a product containing lower oxides of nitrogen ; these can, however, be completely oxidised to the peroxide by prolonged treatment with a current of oxygen.Some care must be taken during the early part of the reaction, as it is liable to become too violent. The arsenic trioxide should be used in lumps of moderate and uniform size and should not contain any fine powder. The heating must be conducted very slowly and carefully and it is advisable to have a basin of ice- water at hand, as it is occasionally necessary to cool down the flask in order to check the violence of the reaction. The reaction proceeds in two stages, which are fairly sharply defined. In the first of these, practically all the nitrous fumes are absorbed by the sulphuric acid and very little nitrogen peroxide, if any, collects in the receiver. This stage of the reaction proceeds at a fairly low temperature and requires considerable attention, as it easily becomes too violent.I n the second stage, a higher tem- perature is employed, in order to break up the nitrososulphuric acid with the formation of nitrogen peroxide. This heating may be commenced as soon as the mixture in the flask ceases to evince a ten- dency to react too violently when warmed. The reaction is endo- thermic and no more danger is to be feared of the reaction becoming uncontrollable. A copious stream of nitrogen peroxide is evolved. This is first passed through a short reflux condenser cooled by water and then through a glass worm cooled to about -loo, and condenses with practically no loss, even though the distillation be carried on very quickly.After a time, the evolution of nitrogen 5 A 21360 FRANKLAND AND FARMER : peroxide nearly ceases and it is best to break off the experiment at this point. If the heating be continued, a third stage sets in and nitric oxide is evolved. If this be passed into the receiver, it reduces part of the nitrogen peroxide already collected, forming a green solution. The distillate is dehydrated by the addition of phosphoric oxide and further purified by the prolonged action of a current of dry oxygen at a low temperature. The purified liquid, which must be perfectly free from all tinge of green, is then redistilled and kept in stoppered bottles containing phosphoric oxide. I . Nitrogen Peroxide as a Xoluent. In order to examine the solvent powers of liquefied nitrogen per- oxide on various substances, a few grams of the peroxide were brought into a carefully-dried tube and cooled in a freezing mixture.The substance to be examined was then gradually introduced in a fine, dry powder and its behaviour noted. I f it dissolved, so much was added that a nearly saturated solution was formed and the clear liquid was then evaporated down, the nitrogen peroxide being re- covered by means of a spiral condenser in a freezing mixture, The last traces of the peroxide were removed as completely as possible by exbausting the tube, and warming it a t the same time. The residue was then examined as regards melting point and other properties, in order t o ascertain whether any reaction had occurred. Various other methods were employed in order to detect traces of reaction which might be overlooked in examining the residue obtained by evaporation.I n general, any decomposition which an organic compound undergoes shows itself by a green colour which the nitrogen peroxide assumes. I n the case of simple oxidations, this is due to the formation of the trioxide by the reduction ol the peroxide. In cases where a hydrogen atom is displaced, the water formed also acts on the nitrogen peroxide t o form a bright green liquid. The formation of this green tinge is therefore a sen- sitive indication that a reaction has taken place. In the cases in which water is set free, a more delicate indication is given by the electric conductivity. As already mentioned, the smallest trace of water causes the conductivity to rise enormously. A third, and also very sensitive, method was to ascertain whether the boiling point of the liquid rose in accordance with Raoult’s law.If no decomposition occurred, the normal rise of boiling point was observed. If, however, any decomposition took place, the boiling point fell instead of rising owing t o the formation of lower oxides in the solution,LIQUID NITROGEN PEROXIDE AS A SOLVENT. 1361 It is well known that most of the metals are quickly attacked by nitrogen peroxide. Of the non-metals, chlorine is soluble to some extent, bromine is miscible in all proportions, forming a brown solution, whilst iodine dissolves with *extreme ease, forming a purple-brown solution. No reaction takes place between these elements and nitrogen peroxide.XuZphur, on the other hand, is only slightly soluble. Inorgunic Compounds, (i) 8uZts.-No case was found in which an inorganic salt was soluble in nitrogen peroxide. In most of the cases examined, the salts were found to be unacted on by treatment with this reagent. Here again, however, the inertness depends on the complete purity of the peroxide. It was found, for instance, that chlorides were attacked moderately quickly by nitrogen peroxide which had not been completely dehydrated, with evolution of chlorine, but that when pure peroxide was used, no action took place. The general behaviour of liquid nitrogen peroxide towards inorganic salts will be seen by the following results. Potassium nitrate, sulphate, and cldorate, sodium nitrite, mercwic nitmte, and hydraxine sulplhate were neither dissolved nor attacked by the liquid peroxide.Of the halogen compounds, the$uorides and chlorides were unaffected by the pure anhydrous liquid. Potassium chloride was quickly attacked in presence of traces of moisture, with evolution of chlorine, which partly escaped and partly remained dissolved in the liquid peroxide. Potassium bromide and iodide were both attacked, even by the pure anhydrous liquid; the halogen set free remained in solution. Perric chloride was examined, as it is well known to be somewhat soluble in ether. When dried with great care, the forric chloride remained unaffected by the liquid, but in presence of traces of moisture it was quickly attacked and the solution was found afterwards to contnin traces of iron.The iron compounds of the diketones were also examined on account of the interest which they possess as being pseudo-salts, non-ionised in aqueous solution and dissolving easily in indifferent organic solvents. The deep-red iron compounds of acetonylucetone, Fe(C,H,O,),, and bertxoylacetone, Fe(C,oH,0,)3, were employed, but were both immediately attacked and no iron was found in the solution. Mercuk cyanide was tried as being a further example of a pseudo- salt, but remained entirely unaffected. It may be stated in general that inorganic salts are undissolved and in the majority of cases unattacked by liquid nitrogen peroxide. (ii) Inorganic Acids.-Aqueous hydrochloric acid has been long known to react with nitrogen peroxide, forming nitric acid and aqua1362 FRANKLAND AND FARMER : regia.The behaviour of dry hydrogen chZhloride does not appear to have been examined. We find it to be ontirely without action, as was shown by the fact that the solution showed no green tinge and possessed no measurable electric conductivity, SuZphu~ic acid remained at first unaffected, Gradually, however, it combined with the peroxide to form a solid mass of ' chamber crystals ' with evolution of heat, The resulting compound was insoluble in nitrogen peroxide, but could not be induced to crystallise, and its composition is therefore at present unknown. It appears, however, to be a nitrosophosphoric acid, as it reacts with water in exactly the same way as nitrososulphuric acid, with evolution of nitrous fumes, Bo~ic and iodic acids were unattacked and undissolved by nitrogen peroxide. Phosphoric acid was found to absorb some nitrogen peroxide.Organic Compounde. As inorganic salts were found to be insoluble in liquid nitrogen peroxide, its effect on organic compounds was next examined. It was a t first thought that almost all organic compounds would be immedi- ately acted on when brought together with the liquid, and considerable precautions were taken when introducing the substances. A great many organic substances can be introduced into it with impunity and i t is only in exceptional cases that it reacts with such violence as to render the experiments in any way difficult to carry out. As was to be expected, the presence of small quantities of water increased the chemical activity of the peroxide greatly.Many of the following substances which were unattacked by the pure peroxide were decom- posed by treatment with a product containing traces of water. As a solvent, nitrogen peroxide takes up most organic compounds with considerable ease. I n some cases, the compounds were so easily soluMe that they only crystsllised out when almost all the nitrogen peroxide had been removed by evaporation. As a general rule, the substances which dissolved easily in nitrogen peroxide were also soluble in ether, although a few exceptions to this rule were noted, 1iquid.nitrogen peroxide being usually the more powerful solvent of the two. Thus cane sugar and tartaric acid, although insoluble inether, were bothsoluble in nitrogen peroxide ,Lad were unattacked by the pure solvent.As a general rule, the saturated hydrocarbons, their halogen and nitro- derivatives and the carboxylic acids, as also ketones and quinones, were stable towards this reagent, whilst the hydroxy- and amino- compounds were quickly attacked. In the case of the aromatic hydroxy- compounds which were attacked, the nitrogen peroxide brought about The liquid was, however, soon found to be surprisingly inert.LIQUID NITROGEN PEROXIDE AS A SOLVENT. 1363 a nitration, aniline derivatives were diazotised, and in some other cases simple oxidation took place. The following results will show the general behaviour of nitrogen peroxide to wards organic compounds :- (i) Hydrocu~bons.-The unsaturated hydrocarbons have already been shown by Guthrie (Annalen, 1860, 116, 248) and others to take up nitrogen peroxide.Thus amylene forms the so-called nitrosate, N0,*O*C5H,:N*OH. Benzene and toluene are both miscible with nitrogen peroxide and are unacted on by it. Naphthalene could not be dissolved unchanged ; it was quickly attacked and gave rise to 1 : 5- dinitronaphthalene (m. p. 211°), which is also formed by the nitra- tion of naphthalene with nitric acid, Anthracene was oxidised to anthraquinone, which could be easily sublimed in yellow needles melting at 273'. Pure paraffin wax, consisting of higher aliphatic hydrocarbons, appears to be unchanged by nitrogen peroxide ; it could be recovered unchanged after remaining for several days in contact with the liquid. Most specimens, however, disintegrated quickly in contact with the liquid, probably owing to reactions between the peroxide and the impurities in the paraffin..,' (ii) Nitro-derivatives are generally very stable towards nitrogen peroxide. Nitrobenzene, m-dinitrobennxene, p-nitrotoluene, and 1 : 5-di- nitronaphthalene were all easily soluble in it. The normal rise of boiling point of their solutions showed that no reaction had taken place. They were also recovered by evaporation and identified. Other nitro- derivatives are mentioned under the heading of carboxylic acids and hydroxy-compounds. (iii) Halogen, derivatives are also very stable. Chlorojorm and chlorobenxene were already known to dissolve unchanged. Besides these, we have found ethylene dibrornide, ucetylene tetrabromide, and benxyl chloride to dissolve in all proportions without reaction.(iv) Curboxylic Acids.-Of these, a considerable number have been examined and have in almost every case been recovered unchanged from the solutions. In most cases, the absence of all reaction was confirmed by the electric conductivity and other methods. E'ormic, acetic, monochloracetic, trichlorcccetic, tribromacetic, tri- chlorobutyric, tarturic, and benxoic acids were extremely easily soluble. 0-, m-, and p-Nitrobenxoic ucids, the three bromobenxoic and toluic acids, as also succinic and phthalic acids dissolved only with difficulty. In all these cases, the pure substances were recovered by evaporation. Slightly impure nitrogen peroxide readily attacks tartaric acid. Benzoic acid was also attacked to some extent in presence of moisture, forming a trace of m-nitrobenzoic acid, (v) Hydroxy-compounds.-Alcohols and phenols were less stable towards nitrogen peroxide than the above-mentioned compounds.1364 FRANKLAND AND FARMER : Ethyl alcohol reacted violently with evolution of heat, forming ethyl nitrite.It was not decomposed by the pure peroxide, but was quickly attacked in presence of traces of moisture. When the liquid peroxide was added gradually to phenol, the first products of the reaction were o- and p-nitrophenol (compare Armstrong and Rossiter, Proc., 1891, 7,92). These were, however, only intermediate products, and were completely converted into 2 : 4-dinitrophenol by excess of the peroxide; no picric acid was formed. o- and p-Nitro- phenol were both quickly attacked and the product was in both cases the same 2 : 4-dinitrophenol.2 : 4-Dinitrophnol was easily soluble in liquid nitrogen peroxide and was recovered unchanged ; no picric acid was formed. Trinitvophenol (picric acid) was very easily soluble in nitrogen per- oxide and was unattacked. Salicylic acid dissolved at first, but was quickly attacked, crystals separating out. The chief product of the reaction was 5-nitrosalicylic acid, but a small quantity of picric acid was also found in the residue. 5-Nitro~alicyZic acid was difficultly soluble and was not attacked. (vi) Amines were immediately attacked. It has been long known that gaseous nitrogen peroxide acts on aniline, forming diazobenzene nitrate (Witt, Z"?agbl. Naturforsclier-Vers., 1879, 194). Liquid nitrogen peroxide reacts with explosive violence on aniline, but the reaction proceeds more quietly when a dilute solution of nitrogen peroxide in carbon disulphide is used, and the diazo-compound separates out. The action of the liquid peroxide on substituted anilines is less violent, the diazo-compound crystallising out from the solution.In this way, o-, m-, and p-nitraniline and P-naphthylamine mere converted into the corresponding diazo-compounds. Pyridine and quinoline were violently attacked by liquid nitrogen peroxide, giving dark coloured products which could not be identified. (vii) Quinode was easily soluble and anthraquinone sparingly so in the liquid peroxide, and were both unattacked by it. Cane sugar dissolved fairly easily in nitrogen peroxide. Phenol also reacted vigorously with evolution of heat.11. Electric Conductivity of Xolutions in Liquid Nitrogen P e r o xi d e. On account of the ease with which nitrogen peroxide can be lique- fied, the measurement of the electric conductivity of its solutions presented no great difficulties. A temperature of Oo was sufficiently low t o prevent any considerable evaporation of the solvent and the following experiments were all carried out at this temperature.LIQUID NITROCEN PEROXIDE AS A SOLVENT. 1365 Measurements of the electiical resistance of pure liquefied nitrogen peroxide have already been made by Boguski (Zoc. cit.), who sealed up liquid nitrogen peroxide in tubes fitted with platinum electrodes and then determined the resistance by means of a momentary current and a galvanometer.We have confirmed his observation to the effect that the conductivity of the pure liquid is exceedingly small, bnt that a trace of water suffices to render i t a very good conductor. Thus the addition of about 2 per cent. of water gave a solution which conducted at least as well as a X / l O O solution of nitric acid. Measurements of the electric conductivity of solutions of various substances in liquid nitrogen peroxide do not appear to have been made. The method used in the following experiments was the same as that usually applied to the determination of electric conductivity in aqueous solution. A Wheatstone bridge with alternating current and telephone was used. The ,electrodes were fixed very close to one another, so that very small conductivities could be easily measured.A cylindrical glass conductivity vessel of the usual form mas used, but it was fitted with an asbestos cover, the usual wooden cover being out of the question on account of the ease with which it is attacked by the fumes. A glass stirrer was provided with which to facilitate the solution of the compounds. I n general, the nitrogen peroxide itself showed a slight but measur- able conductivity, but this was due to the presence of traces of water. When no great precaiitions were taken to remove all traces of water, the liquid generally showed a specific conductivity of 0.1 to 0.2 x 10-6 units, The quantity of water present was too small to show itself by any green tinge in the liquid, but it could be proved that the conduc- tivity was to be attributed to this cause by the fact that when a little phosphoric oxide was added, the conductivity gradually decreased until it became absolutely unmeasurable.We have assured ourselves that, with the apparatus used by us, a specific conductivity of 0.02 x could still be detected with certainty. If we compare this with the specific conductivity of about 0.65 x 10-6, which is found for water which has been purified with great care (Walker and Cormack, Trans,, 1900, 77, 5), we see that pure nitrogen peroxide is an almost perfect non-conductor of electricity. The following experiments will show that its solutions are likewise non-conductors. As above mentioned, the only available compounds for these conductivity measurements were acids, all bases being excluded on account of their instability, and salts on account of their insolubility, in this solvent.A saturated solution of dry hydrogen chloride in liquid nitrogen peroxide was first examined, but showed no measurable conductivity. The following organic acids were then tested in nitrogen peroxide solution : Formic, acetic, monochloracetic, trichloracetic, trichloro-1366 FRANKLAND AND FARMER : butyric, malonic, succinic, benzoic, o-toluic, m-nitrobenzoic, phthalic, and picric acids. Fairly concentrated solutions were employed, in most cases about 1/5 normal. These solutions were found, without exception, to be practically absolute non-conductors. It may therefore be safely con- cluded that substances dissolved in liquid nitrogen peroxide are not electrolytically dissociated.111. Molecu Zar We g h t Determinations in Liquid Nitrogen Peroxide. Having shown by measurements of the electric conductivity that no dissociation occurs in nitrogen peroxide solution, we thought it would be of interest to examine the state of molecular aggregation more fully by a series of molecular weight determinations. Ramsay has already determined the lowering of the freezing point of nitrogen peroxide by a few dissolved substances (Zoc. cit.), but found the measurements difficult to carry out. Experiments on the raising of the boiling point do not appear to have been made, and this method was chosen for the following determinations. The experiments do not present any unusual dificulties; a freezing mixture of ice and salt suffices to condense the nitrogen peroxide vapour with practically no loss.In the outer jacket, acetaldehyde was used, as it is naturally preferable to employ a liquid which does not attack rubber and cork. Its boiling point (20.8') is almost the same as that of nitrogen peroxide (21~6~). The nitrogen peroxide in the inner tube was caused to boil evenly by means of glass beads and platinum foil. The connection between the inner vessel and the spiral condenser was made as shown in the diagram (p. 1367). The condenser tube fitted loosely into the side tube of the boiling vessel, and the joint, A, was made tight by means of asbestos paper bound round with wire and coated with vaseline, the latter being frequently renewed during the experiment. In order to introduce the substance without making an open passage for the peroxide to escape into the air, the glass piston, C, - was temporarily removed and the cylindrical lumps of substance, previously weighed, were introduced into the tube B.The piston, C, was then replaced and the whole condenser raised so as to make an open connection between B and the boiling vessel. By means of the rod, C, the substance was quickly pushed down so that it fell into the boiling vessel, and the condenser lowered into its original position. Thus, the escape of nitrogen peroxide during the experiment was reduced to a minimum. The ordinary Beckmann apparatus was employed.LIQUID NITROUEN PEROXIDE AS A SOLVENT. 1367 The thermometer, D, was held in place by a stopper, E, made by rolling asbestos paper into a solid plug, and heating this for some time in molten paraffin wax.This was found somewhat pre- ferable to a stopper of plaster of Paris, which was originally em- ployed. In either case, the joints were made tight with vaseline. A number of preliminary experiments showed that the loss of liquid was inconsiderable, even when the boiling was protracted for many hours. I n order to give satis- factory results, the nitro- gen peroxide must be com- pletely freed from lower oxides by previously pass- ing a current of oxygen through it for a consider- able time at about - lGO. After each experiment, the peroxide was recovered by distillation and the residue examined to make sure that no decomposition had occurred. I n most cases, the redistilled liquid mas resat urat ed with oxygen before being used again, as the prolonged boiling necessary in the determina- tions sometimes brought about a slight reaction be- tween the solvent and the dissolved substances, by which traces of lower oxides of nitrogen were formed.The constant for the E raising of the boiling point was first ascertained with a number of indifferent substances, for which there was no likelihood of the formation 'of complex molecules in solution. The following tables show the constants found for 1 gram-molecule of substance in 100 grams of solvent :1368 FRANKLAND AND FARMER : Grams of solvent. Grams of substance. Rise of boiling point. Grams of substance in 100 grams of solvent. Constant. Nitrobenzene, C,H,*NO,. Mol. mt. 123. 53 '6 53.6 53-6 53 *6 53.6 53.6 53 -6 53 '6 1.012 1 '591 2.352 3.108 4.227 5-569 7-250 11-792 0,215 0.317 0'464 0.612 0'841 1.105 1'457 2.394 1-89 3 '01 4'39 5.80 7'89 10-39 1352 22'00 m-Dinitrobenxene, C,H,(NO,),.Mol. wt,. 168. 44 '2 44-2 44.2 44.2 44.2 44-2 40-6 39.9 39.1 38'4 37.6 36 *9 36.1 0.601 1 *447 2.238 3 *296 4.170 5.045 0.449 1.098 1.707 2.331 2'959 3-413 4.410 0.110 0.250 0,392 0.581 0.743 0.902 0.085 0.216 0.342 0.490 0.625 0.717 0'949 1'36 3 '27 5.06 7.46 9'44 11 '42 1'11 2-75 4 '37 6 -07 7 '87 9.25 12'22 41.8 41 -8 41 '8 41 *8 0-337 1 -037 2.904 4'106 0.077 0'247 0.691 0.990 Y'oZuene, C,H,*CH,. Mol. wt. 92. 49 *3 49 '3 49'3 49 '3 1.234 2.661 3'989 5.375 0.379 0.830 1 '233 1 *637 0.81 2.48 6.95 9'82 2.50 5 -40 8'09 10'90 14.0. 13.1 13.0 13'0 13.1 13 :1 13.2 13.4 13% 12.8 13'0 13'1 13 *2 13.3 12.9 13.2 13.2 13.6 13.3 13-0 13.1 13.1 13'6 13-6 13'8 13.9 14'1 14.0 1323LIQUID NITROGEN PEROXIDE AS A SOLVENT.1369 Grams of substance in 100 grams of solvent. I I I I Constant* Grams of solvent. Grams of substance. Rise of boiling point. Benxyl chZo?*ide, CGH,*CH,Cl. Mol. wt. 126.5. 61.0 61 *O 61'0 61-0 61 -0 61.0 61.0 0.750 2-538 3.558 4'944 7.052 9'010 10.811 0,139 0'476 0'662 0.916 1'289 1.627 1 1'926 Acetplene tetrabi*omide, C,H2Br,. Mol, 52.6 52'6 52.6 52'6 1.336 4'190 7-663 9'915 0.101 0'340 0.607 0'743 1 *23 4'16 5 *83 8.11 11 '56 14'78 17.72 wt. 346. Ethylene clibvomide, C,H4Br2. Mol. wt. 188. 2 *54 7.97 14-57 18-85 50.9 50.9 50 -9 50 '9 50 -9 50.9 50.9 0.880 2-487 3'976 5-340 7.41 7 11.575 15-5U3 0'134 0'387 0.620 0.824 1 -102 1.650 2,127 46.5 46'5 46.5 0'687 1.199 1.675 0.181 0-328 0'462 Acetopheno?ae, C,H,-CO*CHB.3x01. wt. 120. 59'8 59'8 59 *8 59.8 59 -8 1'902 2.741 3.972 5.094 6'161 0.345 0'524 0.768 0.987 1'195 1 '73 4'89 7 -81 10'49 14.57 22*75 30-45 1 -48 2'58 3 '60 3.18 4 '58 6 '64 8 *52 10'30 14'3 14.5 14'4 14.3 14-1 13'9 13.8 1308 14 *8 14.4 13 '6 14.6 14'9 14'9 14-8 14.2 13'6 13.1 13 -2 13'7 13-9 13'0 13.7 13.9 13'9 13'913'70 FRANKLAND AND FARMER : Weight of in grams. The following is a list of the mean constants found in the above experiments : Substance. Mean constant. Nitrobenzene .................................. 13.2 Dinitrobenzene (1st series) ............... 13.2 ............... 9 9 (2nd series) 13.2 p-Nitrotoluene .............................. 13.5 Toluene .......................................14.0 Benzyl chloride .............................. 14.2 Acetylene tetrabromide., ................... 14.2 Ethylene dibromide ........................ 14.3 Quinone ....................................... 13.6 Acetophenone ................................. 13.7 - Mean 13-7 Grams of Weight of Rise in substance in in boiling point. 100 grams of solvent. grams. The fifty-five observations comprised in these ten series rarely deviated by more than 5 per cent. from this mean value. The number 13-7 may therefore be safely concluded to be aclose approximation to the constant for 1 gram-molecule of substance dissolved in 100 grams of liquid nitrogen peroxide. Our attention was next turned to the examination of the acids the electric conductivity of which we had previously inveqtigated.The results of our experiments show that many acids are associated in nitrogen peroxide solution and exist in the form of double molecules. Association is well known to take place in certain other solvents (benzene, &c.). At the lowest concentration taken, namely, 2.45 per cent., benzoic acid was not quite completely associated to double molecules. A t a concentration of 5 per cent., however, the association was practically complete and remained nearly constant a t the higher concentrations, 42.9 42.9 42 '9 42'9 Benxoic Acid. 1.049 0.160 2 -048 0.277 2-952 0'411 3'973 0.556 C,H,*CO,H; mol. wt. 122. (C6H,*C02H), ; mol. wt. 244. Molecular weight (found), I I I 1 I 2.45 4-77 6-88 9 '26 2 09 236 229 228LIQUID NITROGEN PEROXIDE AS A SOLVENT.1371 In dealing with the substituted benzoic acids, we were met with the difficulty that most of the acids in question were sparingly soluble in nitrogen peroxide, as in other solvents. Even at, the highest con- centration taken, the association to double molecules was incomplete. It will be seen, nevertheless, from the following figures that the acids are strongly associated and we may assume that they would exist in the form of double molecules in more concentrated solutions, o-Toluic acid was the most easily soluble of those tried, but its association was still somewhat incomplete at the highest concentrations employed. Toluic Acids. CH,*C,H,*CO,H ; mol. wt. 136. (CH,eC6H,*C0,H), ; mol. wt. 272. Weight of solvent in grams. 51 -0 51 *O 51 -0 51'0 51.0 51 -0 51.0 51 -0 51.0 51 '0 51.0 57 '8 57.8 substance in Molecular I I 0.223 0.723 1.277 1 *869 2'450 3.189 4.176 0.265 0'712 1.013 1.362 0'581 1'074 0.030 0.086 0.141 0.211 0.279 0.353 0.463 m-Zbluic acid.0.036 0.085 0.120 0.160 p-Toluic acid. 0.071 0.129 0'44 1-42 2-50 3.66 4 *80 6.25 8.19 0'52 1 -40 1-99 2.67 1 *01 1.86 200 226 243 238 236 243 242 198 225 227 229 194 197 Experiments with the nitrobenzoic acids failed to give satisfactory values, the acids being very sparingly soluble in nitrogen peroxide. The measurements taken in dilute solution pointed, however, to a con- siderable association. Experiments were also commenced with the bromobenzoic acids, but were discontinued for the same reason. A similar association was found for the acids of the aliphatic series.1372 LIQUID NITROGEN PEROXIDE AS A SOLVENT.Weight of Weight of solvent in substance in grams. grams. For acetic acid, only the first of a series of measurements is given, the others having been rendered inaccurate by a slight decomposition which the nitrogen peroxide underwent, It is sufficient to show that a complete association to double molecules had taken place. Grams of substance in Molecular 100 grams of weight (found). Rise in point. 1 Acetic Acid. CH,*CO,H ; mol. wt. 60. (OH,-CO,H),; mol. wt. 120. 57'8 1,608 1 0.313 1 2.78 122 Tribromacetic Acid. CBr,*CO,H; mol. wt. 297. (CBr,*CO,H), ; mol. wt. 594. 55 '9 55.9 55 '9 0.518 1.192 2.126 0.023 0.051 0.086 0.93 2-13 3-80 552 573 606 Trichlorobutyric Acid. C',H,Cl,*CO,H ; mol. wt. 191.5. (C,H,Cl,*CO,H), ; mol. wt. 383. 54'5 54.5 54 -5 54.5 54.5 54.5 54.5 0.464 0'839 1'378 1 '943 2.602 3.350 3.797 0.050 0.085 0.133 0'185 0.245 0'308 0.340 0.85 1 *54 2-53 3'57 4'77 6'15 6 '97 233 248 260 264 267 273 281 The association will be seen to be much less complete in the case of trichlorobutyric acid. Since acids showed a tendency to form complex molecules in nitrogen peroxide, an examination of the phenols seemed desirable. As men- tioned above, most phenols are readily attacked by nitrogen peroxide. The choice of available phenols was therefore limited. In the following cases, the normal molecular weights were found :ACTION OF AT,UMINIUM CHLORTDE ON CAMPHORIC ANHYDRIDE, 1373 Weight of solvent in grams. Grams of substance i n boiling point. 100 grams of solvent. Weight of grams. substance in Rise in Molecular weight (found). 49 *3 49 *3 49 *3 ~~ 2 : 4-Dinitrop7tenoZ, OH*C,H,(NO,),. Mol. wt. 184. 0.227 ~ 0.034 0 ’480 3-074 0-862 0.135 41 ‘0 40.4 39’8 39.3 38.7 0.46 0.97 1‘75 0.939 0.143 2.29 1.675 0 *243 4.15 2.405 0.350 6.04 3.151 0.448 8-02 , 4-061 0.559 10.50 186 180 177 219 234 237 245 257 IV. Xummary of Results. On the other hand, it is a good solvent for certain non-metallic elements and readily dissolves many organic compounds. 2. The perfectly anhydrous liquid is comparatively inert as a chemical reagent ; many organic compounds can be recovered unchanged from their solutions in nitric peroxide. 3. Measurements of the electric conductivity show that it is not an ionising solvent.” 4. Molecular weight determinations show that many substances are 1. Nitrogen peroxide does not dissolve inorganic salts. associated to double molecules in this solvent, UNIVERSITY OF BIRMINGHAM.

ISSN:0368-1645    

DOI:10.1039/CT9017901356

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

ACTION OF AT,UMINIUM CHLORTDE ON CAMPHORIC ANHYDRIDE, 1373 CXLV.-The Action of Aluminium Chloride on Camphoric Anhydyide. Part 11. By W. H, PERKIN, jun., and J. YATES. IN the first part of this paper, published a short time ago (Lees and Perkin, this vol., 332), it was shown that when camphoric anhydride, dissolved in chloroform, is treated in the cold with aIuminium chloride, the camphor molecule undergoes a series of remarkable molecular changes. VOL. LXXlX. 5 B1374 PEREIN AND YATES: THE ACTION OF ALUMINIUM The substances formed during this decomposition and described in the first paper were solauronolic acid, CMe Me,Q/Ny*CO,H CH2-CH, and a mixture of isomeric lactones, which, since they are readily con- verted into xylic acid on oxidation with sulphuric acid, were recognised as stereoisomeric modifications of the lactone of hydroxyhexahydro-xylic acid, CMe CH By hydrolysing the mixed lactones we succeeded, in a way described in detail in that paper, in isolating two well characterised stable hydroxyhexahydro-xylic acids melting at 160' and 1 13' respectively, which we called simply A and B, since we had no means of determin- ing their configurations. When distilled, these acids were converted into the corresponding lactones with elimination of water, the lactone of the A-acid melted at 55O,* and that of the B-acid a t 44O.We have since further examined these two hydroxy-acids and their lactones and find that the A-acid or its lactone, when treated with fuming hydrobromic acid, is converted into A-bTo~o~xah~dTo-xyZ~c m i d , CBrMe CH,/)CH, CH),/CHM~ aHC0,H which melts at 133', whereas the B-hydroxy-acid and its lactone, under similar conditions, yield B-bromohexahydro-xylic acid melting at 1269 In our earlier experiments, several results were obtained which seemed t o indicate that the lactone mixture obtained by the action of aluminium chloride on camphoric anhydride did not consist entirely of the two lactones of A- and B-hydroxyhexahydro-xylic acid, but contained other isomeric lactones, which we were at that time unable to isolate.Since then, by experimenting with large quantities of material, this * This lactone was described as an oil, but it subsequently solidified,CHLORIDE ON CAMPHORIC ANHYDRIDE. PART 11. 1375 suspicion has been confirmed and we have now been able t o identify all the constituents of the mixture.The two hydroxy-acids, A and B, are chnracterised by remarkable stability, since, although they contain the hydroxyl and carboxyl groups in the &position, they are not converted into their lactones even by prolonged boiling with water, and it was found neccssary, in order to prepare these lactones, to submit the acids to dry distillation." I n order to explain this remarkable stability, we suggested in the earlier paper that the two hydroxy-acids, A and B, were probably the trans-modifications, OH-Me /\ / \ \ M e T H I I and \ H T M e I H-CO,H \/ H.\--/co,H The corresponding &s-modifications, MeTOH e-OH might be expected to exhibit much less stability, and be converted into their lactones when their salts are acidified, as is the case with the 6-hydroxy-acids in the fatty series.* Somewhat similar cases of stable ring hydroxy-acids have already been ob- served. Thus, the hydroxycyclohexanecarboxylic acid of the formula CH2 J H , n C H * O H CH,\/CH, ' CH'C0,H which Einhorn (Annabn, 1896, 291, 298) prepared by reducing m-hydroxybenzoic acid, is quite. stable although it is a y-hydroxy-acid. Again, Tiemann and Semmler (Ber., 1895, 28, 2143) describe as stable the y-hydroxyhexahydro-p-toluic acid of the formula : CHMe c (\~CH*OH CH,\/CH, ' CH*CO,H Both these acids are probably trans-modifications. The existence of cis- and trans-isomerism in the case of ringacids containing t h e 5 B 21376 PERKIN AND YATES: THE BCTION OF ALUMINIUM By making use of these differences in stability we have now suo- ceeded in showing that the mixed lactones obtained by the action of aluminium chloride on camphoric anhydride contain, not only the lactones of the trans-h- and B-hydroxyhexahydro-xylic acids, but also the corresponding cis-lactones. The process employed in separating the latter is briefly as follows : The mixed lactones are first converted into the hydroxy-acids by hydrolysis and these then submitted to distillation in steam ; in this way, the cis-hydroxy-acids are converted into lactones which pass over with the steam, whereas the trans-acids remain for the most part un- changed in the distilling flask, so ithat by repeating this process an almost complete separation is possible. The last traces of trans-acids are removed by hydrolysing the lactones and allowing the hydroxy- acids t o stand for a few days, when the cis-modifications are spon- taneously converted into lactones, which are separated from any traces of trans-hydroxy-acids by treatment with sodium carbonate.In this way, more than 100 grams of oil were obtained, which distilled constantly at 145' under 25 mm. pressure, and, like the trans-lactones, yielded xylic acid when treated with sulphuric acid; there can therefore be no doubt that it consisted of the cis-lactones of hydroxyhexahydro-xylic acid. Further examination showed that this oil contains two lactones (one, however, only in extremely small quantity), since when treated with fuming hydrobromic acid the oil yields a solid product which, when crystallised from light petroleum, may be separated into a small quantity of a very sparingly soluble 0-bromohexahydro-xylic acid melting at 13'7' and a large quantity o f .the more soluble D-bromo- hexahydro-xylic acid, which melts at 130'. A t first it was thought that the two bromo-acids, A and C, melting a t 133O and 137O, and the two B, and D, melting at 128O and 130' were identical, but investiga- tion showed that this is not the case. If, for example, the first two are intimately mixed, the mixture melts at about 100' and a mixture of the two latter was found to melt a t about 105", and again, the four bromo-acids differ in their behaviour with sodium carbonate : a point which will be discussed a t a later stage. groups CHMe and CH*CO,H has already been observed. Thus, hexahydro-o-toluic acid, CH, CH ()CHI CH,\/CHMe ' exists in well-defined cG- and tram-modifications (Goodwin and Perkin, Trans., 1896, 67, 121).CH*C02HCHLORIDE ON CAMPHORIC ANHYDRIDE. PART 11. 1377 + a - a I + a - a + a - a + c - c - c + c - c + c + b - b + b - b I - b + b - a + a - c + c + b - b 1 2 3 4 5 6 7 81378 PERKIN AND YATES: TEE ACTION OF ALUMINlUM following very interesting aspect of the subject, since it arises directly from our experimental work. It has already been stated that the results briefly described above leave little room for doubting that during the conversion of d-cam- phoric acid the change proceeds in such a way as to yield the four externally compensated hydroxyhexahydro-xylic acids, to which only the configurations given on page 1377 can be assigned.It thus follows that the camphor residue has, during the treatment with aluminium chloride, undergone racemisation in a manner similar to, although probably more complete than, that observed by Kipping and Pope (Trans., 1897, 71, 956) to occur on sulphonating camphor ; and whilst in the latter case the complex +a + b became converted into - a - b, in the case now described the other two complexes, + a - b and - a + b, are also produced a t some stage during the series of reactions. The formation of a third asymmetric carbon atom in addition to the two already present results in the ultimate production of all eight possible configurations of the substance containing three dissimilar asymmetric carbon atoms. Quite recently (Cohen and Whiteley, Proc., 1900, 18, 212; Kipping, ibid., 226), the question has again been opened as to whether in con- verting an optically active substance containing wasgmmetric carbon atoms into one containing n + 1 such atoms, the configuration of the %-asymmetric carbon atoms originally present exercises a directive influence on the configuration of the new asymmetric carbon atom. This question seems to have been answered in the affirmative by Fischer's work, and more especially by his observation that d-mannose, which contains four asymmetric carbon atoms, gives an almost quanti- tative yield of d-mannoheptonic acid (Bey., 1889, 22, 370), which contains five asymmetric carbon atoms in the molecule.A number of well-known facts leading to the same conclusion are available and the work now described also points in the same direction.Thus, it is well known that on brominating succinic acid two optically inactive dibromosuccinic acids are obtained in different quantities, the isomeride (bodibromosuccinic acid) produced in much the smaller amount having the configuration [ + a + a, - a - a], whilst ordinary dibromosuccinic acid is the internally compensated compound having the configuration [ + a - a]. Since monobromosuccinic acid containing one asymmetric carbon atom is first produced and on further brom- ination yields more internally than externally compensated dibromo- succinic acid, it follows that the presence of one asymmetric carbon atom in this case causes the second to assume, by preference, the opposite configuration to the first.The literature concerning the tartaric acids reveals similarly convincing proofs of the same pro- position. The possibility of drawing, from the behaviour of opticallyCHLORIDE ON CAMPHORIC ANHYDRIDE. PART 11. 1379 inactive substances, sound conclusi,ons as to the directive influence exerted by the configuration of asymmetric carbon atoms already existent in the substance upon that of others ultimately produced, seems hitherto to have been overlooked. In the formation of the hydroxyhexahydro-xylic acids with three asymmetric carbon atoms from camphoric acid containing only two, we show that the four externally compensated isomerides produced are formed in widely different proportions, which may be roughly stated to be as follows : A, 12 per cent.; B, 5 per cent, ; C, 3 per cent.; D, 80 per cent.Although we are unable at present to definitely distribute the four pairs of possible configurations amongst these four acids, the fact that these acids are formed in different quantities is convincing proof that the configurations of the two original asymmetric carbon atoms have exercised a directive influence on the configuration of the carbon atom, which becomes asymmetric during the action of the aluminium chloride. When the four bromo-acids, A, B, C, D, are boiled with sodium carbonate, they are all decomposed with elimination of hydrogen bromide and formation of tetrahydro-xylic acids, C,H,,O,Br = C,H1402 + HBr, and according to theory, four different externally compensated acids should be formed in this way, as will be seen at once if the bromo- acids aro represented graphically and the corresponding tetrahydro- xylic acids written underneath.Me-Br Me-Br Br-Me /\ Br-Me /\ ".( iH2 H2( 1". H2( I 2 H ' i i". "./". pr /< H , F ) H 2 /\H /\ H2, H T M e H2\ M e T H H2, €€/Me H,\ M e F H v C02H-H \/ CO,H-H \/ C02H-H \/ C02H----H c / Y cis-Acids, C and D. BromoTLexnkyclro-x~lic acids. Me Me H2, H T M e H2\ M e T H Hz\ H T M e i". H2, Me,-H \/ \/ C02H-H v C02H -H C02H-H \/ C02H-H \ 2 L I V Y A and B. C and D. Tctmhydro-xylic acids. As in this change (elimination of hydrogen bromide), only one of1380 PERKIN AND PATES: THE ACTION OF ALUMINIUM the three asymmetric carbon atoms in the bromohexahydro-xylic acids disappears, each of *the unsaturated acids formulated above still contains two asymmetric carbon atoms and is an externally compen- sated compound ; the optical relationship of these four racemic com- pounds may therefore be expressed by the same signs as before, omitting that given to the > CMeBr-group.The tetrahydro-xylic acid, C, will therefore be [ - c - b; + c + b], D mill be [ - c + b, + c - b], and A a n d B will beeither[+c+b,-c-b] or [-c+b,+c-bb]. The actual results of the experiments on the behaviour of the four bromo-acids with sodium carbonate shorn that the three bromo-acids, A, B, and D, give three distinct tetrahydro-xylic acids, A, B, and D, which melt at SOo, 6S0, and 87" respectively, but in the case of the bromo-acid, C, the material at our disposal was so small that we were unable to purify the acid formed sufficiently to determine its melting point accurately ; most probably it is the fourth isomeride indicated by theory.There is, however, a t present no proof of the actual position of the double linkings in the tetrahydro-xylic acids, and the formuls given above are only intended as examples of the direction in which elimination OF hydrogen bromide may possibly take place. It is clear that the relationship, for example, between the cis-bromo- acids, C and D, equally well be and their corresponding tetrahydro-xylic acids might written thus : V e y B r Me Me / .\ I n order, i.f possible, to obtain some clue as to the constitution of these unsaturated acids, experiments (see pp. 1388, 1393) were insti- tutedon the oxidation of the tetrahydro-xylic acids, A and D, but the results obtained with the small quantities of these acids available were not sufficient to throw much light on this point.When treated with fuming hydrobromic acid, the three tetrahydro xylic acids A, B, and D are quantitatively reconverted into the bromo-acids from which they were derived by elimination of hydrogen bromide, the bromine atom becoming attached in each case, therefore, t o the tertiary carbon atom carrying the methyl group Another characteristic of these acids is that when warmed with sulphuric acid a t SOo they are rapidly oxidised to xylic acid and, indeed, this change takes place at the ordinary temperature if the solution in sulphuric acid is allowed to stand for some days.CHLORIDE ON CAMPHORIC ANHYDRIDE. PART IT. 1381 During the course of a series of experiments on the reduction of xylic acid by mezzns of sodium and isoamyl alcohol, Bentley and Perkin (Trans., 1897, 71, 173) obtained a tetrahydro-xylic acid which melts a t 1 0 7 O and is isomeric with the tetrahydro-xylic acids, A, E, and D, described in the present paper.That this acid is either Al- or AG-tetrahydro-xylic acid is conclusively proved by the fact that it is formed from methyl a-bromohexahydro-xylate by hydrolysis and elimination of hydrogen bromide. CHMe CHMe CHMe c H,/)cH, CH,/\CH, CH,/\CH, CH/,/CHMe yields CH 2\/ I lCMe Or CH\\/CHMe CEr*CO2Me C*CO,H C*CO,H I n order to obtain further evidence in support of the assumption that the acids A, B, and D are tetrahydro-xylic acids, we decided to further examine this acid of melting point 106', and as the result of our experiments we find in properties and behaviour with reagents it shows a quite striking similarity to the acids A, B, and D.Thus, for example, when heated with sulphuric acid, it is readily oxidised to xylic acid, and it combines readily with hydrogen bromide, yielding a new bromohexahydro-xylic acid which melts a t 1 2 7 O and the constitution of which is doubtless represented by one of the formulae, CHMe CHMe CH,/\CH, or CHBA,,!CHM~ CH,(\CH, CH,,)CBrMe CB.CO,H CHC0,H It is remarkable that the five bromohexahydro-xylic acids described in this paper should all melt between 127' and 137', and that the three tetrahydro-xylic acids, A, B, and D, should all melt close together and be so very similar in properties.The impossibility of readily distinguishing between these different isomeric modifications has very greatly added t o the difficulties of this reseach. EXPERIMENTAL. Sepavation of the Lactones produced by the action of Aluminium Chtoride on Camphoric Anhyhide. I n the introduction, it was stated that a new method for separating these lactones had been worked out, which gives much more satis- factory results than that described in the previous paper and is especially convenient for the rapid isolation of the cis-lactonss. This method is as follows:1382 PERKIN AND PATES: THE ACTION OF ALUMINIUM The solution of the camphoric anhydride in chloroform is first treated with aluminium chloride exactly as described in the pre- vious paper, and after separating the isolauronolic acid by means of potash, the chloroform solution of the lactones is distilled from the water-bath until as much chloroform as possible has been removed.The dark-brown residue, which often still contains 50 per cent. of its weight of chloroform, is fractionated twice under reduced pressure, when the whole passes over at 170-180° (80 mm.) as a colourless oil, the weight of which from 1 kilo. of camphoric anhydride is usually about 130 grams. The mixed lactones from 2 kilos. of camphoric anhydride were now treated on the water-bath with sufficient mode- rately concentrated barium hydroxide to just dissolve them, the solution filtered from a small quantity of a dark-coloured impurity, the filtrate acidified, saturated with calcium chloride, and extracted at least 20 times with pure ether.The ethereal solution was then evaporated and the residual thick oil submitted to distillation in a rapid current of steam (a). When oil ceased to come over with the condensed water, the distillate was saturated with ammonium sulphate, repeatedly extracted with ether, and after evaporating off the ether, the oily lactone mixture was again boiled with barium hydr- oxide until dissolved: the solution was then cooled t o 60°, acidified with excess of hydrochloric acid, and kept a t 60" for 5 minutes. After saturating with calcium chloride, the whole was ex- tracted twenty times with ether ; the ethereal solution was then well washed with strong sodium carbonate (a), dried over calcium chloride, evaporated, and the residual colourless oil distilled under reduced pressure.During the first distillation, the whole quantity passed over at 174-1 77" (80 mm.) and weighed 120 grams ; on distilling again, more tahan 100 grams passed over between 175" and 176" under the same pres- sure. On analysis : 0.1176 gave 0.3017 CO, and 0.099 H,O. This lactone was slightly Iavorotatory, the observed rotation in a 100 mm. tube being only - 4.24O. In order to make quite sure that this oil was quite free from even traces of the lactones of the trans-acids A and B, it was again dissolved in baryta water, and the solution, after standing until quite cold, acidified with excess of hydrochloric acid, care being taken that the temperature did not rise above 159 The whole was then allowed to stand for 24 hours, when it was noticed that the oily layer, which at first was quite thick, had become much more mobile.After extracting as usual with ether, the ethereal solution was washed repeatedly with C=70*0; H=9.3. C9H,,0, requires C = 70.1 ; H = 9.1 per cent.CHLORIDE ON CAMPHORIC ANHYDRIDE. PART 11. '1383 sodium carbonate (c), dried over calcium chloride, and evaporated, when 90 grams of a lactone were obtained which distilled constantly at 145' under 25 mm., and at 2 5 5 O under 760 mm. pressure, and had a rotation in a 100 mm. tube of -5.3'. Experiment showed that further treatment with baryta, exactly as just described, did not alter this rotatioii or the other physical constants of the oil. It was there- fore clear t h a t i t was now quite free from the Iactones of the trans- A- and B-acids, and consisted of the lactones of ths cis-acids only.I n this condition, it was employed in the experiments described in this paper. On analysis, the following numbers were obtained : C,€11,02 requires C = 70-1 ; H = 9.1 per cent. 0.1646 gave 0.4237 CO, and 0.1376 H,O. The density and magnetic rotation of this oil were determined by Density determincctions : d 10°/lOo- 1.0503 ; d 15"]15O = 1.0471 ; C = 70.2 ; H = 9.3. W. H. Perkin, sen., with the following results : d 2O0/2Oo= 1.0441. Mugnetic votution. t. Sp. rotation. Mol. rotation. 15O 1,0562 8.632 These numbers differ considerably from the previous determinations made with the mixture of cis- and trans-lactones, the density was then at 10°/lO'= 1.0606 and the magnetic rotation 8*200, and they natur- ally differ still more for the values found for the lactone of the tmns- acid A (see p.1390), which are as follows : Density, d 10°/lOo= 1.0640 ; magnetic rotation, 8.174. Pormation of Xylic Acid.-The oily lactone just described dissolves in concentrated sulphuric acid with development of a good deal of heat, and if the solution is heated a t 80" i t rapidly darkens and much sulphur dioxide is evolved. After heating for 15 minutes, the product was poured into water and allowed to stand overnight ; the dark precipitate was then collected, dissolved in sodium carbonate, and boiled with purified animal char- coal. On acidifying, a rather dark coloured crystalline mass separated, and this, after drying, was distilled and the distillate crystallised from dilute acetic acid, &when almost colourless crystals separated which melted a t 124-125' and consisted of xplic mid, C,H,(CH,),*CO,H.On analysis : Action of Xulphuric Acid on the cis-lactones. 0.1298 gave 0.3422 CO, and 0.0794 H,O. C = 71.9 ; H= 6.8. C,H,,O, requires C = 72.0 ; H = 6.7 per cent.1384 PEREIN AND PATES: THE ACTION OF ALUMINIUM Sepurc6lion of the Xubstunces Removed during the Purmification of the cis- Lnctones. During the purification of the cis-lactones, as described in the pre- vious section, more than half of the original mixture of cis- and trans- lactones was removed during the steam distillation and afterwards by the repeated extractions with sodium carbonate. The investigation of this material was carried out briefly as follows.The sodium carbonate extract b (p. 1388) was acidified, saturated with calcium chloride, and repeatedly extracted with ether ; the ethereal solution, after care- fully drying over calcium chloride and evaporating to a small bulk, yielded, on standing, I 7 grams of colourless crystals, which, after re- crystallisation from ether, melted at 158-1 60° and consisted of pure A-hydroxyhexahydro-xylic acid (this vol., p. 345). The ethereal mother liquors of these crystals deposited, on spon- taneous evaporation, several crops of crystals which, when left in con- tact with porous porcelain to remove oily impurity, became hard and colourless, and on subsequently recrystallising from ether, yielded further quantities of the A-acid. The total amount of pure A-acid obtained from this sodium carbonate extract was 27 grams.It is rather remarkable that such considerable quantities of the A-acid should be found at this place, since its presence here shows that it must have been carried over during the steam distillation, yet in the previous paper (p. 345) it was shown that the pure A-acid is not volatile as such with steam, nor is it converted into its volatile Iactone under these conditions. It therefore follows that in the pre- sent case its volatility must be due to the presence of the lactones of the cis-acids, which carry it over during the steam distillation. The sodium carbonate extract c (p. 1383) was acidified with excess of hydrochloric acid, when a thick, heavy oil separated, which on standing at the ordinary temperature for 3 weeks became much less dense and more mobile.The whole was then saturated with calcium chloride, repeatedly extracted with ether, the ethereal solution washed well with strong sodium carbonate (d), dried over calcium chloride, and evaporated. In this way, about 80 grams of an oil were obtained which distilled constantly a t 163O (40 mm.), and had a rotation of - 4.4' in a 100 mm. tube. This was further purified by solution in baryta water and treatment with hydrochloric acid at the ordinary tempera- ture, as previously described in purifying the main bulk of the cis-lac- tones (p. 1382) ; it then yielded more than 70 grams of pure cis-lactones. Thus, without allowing for considerable loss during purification, the total yield of the cis-lactones from 250 grams of the mixed lactonesCHLORIDE ON CAMPHORIC ANHYDRIDE.PART 11. 1385 is a t least 170 grams. The sodium carbonate extract d was treated in exactly the same way as c, and yielded small quantities of the cis- lactones and about 0.5 gram of pure crystalline A-acid. The steam distillation flask, a, contained a considerable quantity of a thick oil ; this was repeatedly extracted with ether and after drying the ethereal solution and evaporating, the residual oil was several times carefully distilled. During the first distillation, much water was given off and a colourless oil was collected at 160-170° under 35 mm. pressure, leaving in the flask a slight crystalline residue of camphoric anhydride which had escaped the action of the aluminium chloride. I n order to remove this as far as possible, the oil was care- fully dried and several times slowly fractionated under 35 mm.pres- sure, when almost the whole passed over at 155-160". When this oil was dissolved in baryta water and, after acidifying, the acids extracted with ether, an oil was obtained which, even after standing for months, deposited only a very few crystals; it was there- fore distilled under'the ordinary pressure, when almost the whole quantity came over at 252-255" (750 mm.) The distillate was dissolved in ether and repeatedly extracted with dilute potash, and the alkaline solution, a€ter freeing from ether, was acidified, when a considerable quantity of an oil was precipitated which, on standing, became semi- solid. In contact with a porous plate, the oily impurity was soon absorbed and a crystalline mass resulted, which after crystallising from dilute acetic acid melted at 78-80' and consisted of A-tetrahydro-xylic acid (p.1392). 0.1481 gave 0.3802 CO, and 0.1224 H,O. C,H,,02 requires C = 70.1 ; H = 9.1 per cent. This acid, which weighed about 3 grams, is undoubtedly formed by the elimination of water from A-hydroxyhexahydro-xylic acid, during the frequent distillations, since it is elsewhere proved (p. 1391) that small quantities of A-tetrahydro-xylic acid are always produced when the A-hydroxy-acid is distilled. The ethereal solution which had been separated from the alkaline extract, gave, on evaporation, a colourless oil, and this was converted into the hydroxy-acid by treatment with baryta in the usual way.On long standing, the thick, oily acid partially crystallised and when spread on a porous plate a colourless mass of crystals was obtained, which, after recrystallisation from ether, melted at 158-160O and con- sisted of A-hydroxyhexahydro-xylic acid. The porous plate was broken up and extracted in a Soxhlet apparatus with ether, and the ethereal extract,Iafter a long series of fractional crystallisations, yielded about 2 grams of A-hydroxy-acid and 5 grams of pure B-hydroxy- C = 70.0 ; H = 9.2.1386 PERKIN AND PATES: THE ACTION OF ALUMINIUM hexahydro-xylic acid, which melted at 1 1 3 O and on distillation was decomposed with elimination of water and formation of the pure B-lactone melting at 44". It is remarkable that so little of the B-acid should have been obtained on this occasion, because in the previous experiments (Zoc. cit., p.346), arelatively large quantity of it could always be isolated with comparative ease. This great difference in yield proves that the rela- tive quantity of the lactones formed by the action of aluminium chloride on camphoric anhydride varies with unavoidable slight alterations in the conditions of the experiment. Action of Eydrobromic Acid on the cis-lctctoms of Eydroxyhsxahydro- xylic Acid. Formation of the cis-Jfodz$cations (C and D) of Br omo hexah y dro-x y Zic Acid, Br-Me /\ H2\ Me,-H Br-Me /\ H z f ' IF H2' \iH2 H2( H7Ne C O , H ~ H C O ~ H ~ H When the mixed cia-lactones, in quantities of not more than 5 grams are rapidly mixed with four times the volume of fuming hydrobromic acid (saturated at OO), they rapidly and completely dissolve, but in a few seconds the solution becomes opaque owing to the separation of oil, The oil collects as a clear layer on the surface of the acid and after standing for 24 hours solidifies to a colourless, crystalline mass.This is powdered, washed with water on the pump, and left in contact with porous porcelain until quite dry; it is then ground up with light petroleum (b. p. 35-40°), in which it is very sparingly soluble, and washed with this solvent on the pump. The latter operation not only removes traces of coloured impurity but dissolves a small quantity of unchanged lactone, which always appears to be present, even when a large excess of hydrobromic acid is used. The colourless residue is vapidly" dissolved in boiling light petroleum (b.p. SO-SOo), a pinch of purified animal charcoal added, the liquid filtered, and carefully watched as it crystallises. A small crop of prismatic crystals of the C-bromo- acid quickly forms, then there is a pause in the crystallisation, and if the liquid is quickly poured off and well stirred, a mass of needles of the D-bromo-acid rapidly separates. By repeating this operation, it is quite easy to completely separate these two acids. C-Byomohexahydro-xylic Acid crystallises in glistening, prismatic needles and melts at about 137-138' if the determination is rapidly * Unless this operation is very rapidly performed, the bromo-acids decompose with evolution of quantities of hydrogen bromide.CHLORIDE ON CAMPHORTC ANHYDRIDE.PART 11. 1387 carried out, but as it decomposes on heating with evolution of hydrogen bromide, a considerably lower melting point will be observed if t h operation is conducted slowly. Oa21O8 gave 0.1697 AgBr. This C-bromo-acid is very sparingly soluble in light petroleum and so similar in its other properties to A-bromohexahydro-xylic acid (m. p. 1 3 3 O , p. 1391) that it was at first thought that the two were identical. Carefully purified specimens of each of these two acids were therefore intimately mixed, and it was then found that the melting point of the mixture was about 100-105", a conclusive proof that the two bromo-acids C and A are not identical. So far as could be seen with the small quantity of material at our disposal (2 grams dissolved in 100 C.C.of pure ether), C-bromohexahydro- xylic acid is inactive; in dissolves readily in sodium carbonate, and on acidifying the solution and heating to boiling, some of the tetrahydro- xylic acid formed appears to be converted into the C-lactone ; if this is removed by making alkaline with sodium carbonate and extracting with ether and the alkaline solution acidified, an oil separates which solidifies on standing and probably consists of C-tetrahydro-xylic acid. From this small experiment, the C-bromo-acid appears to behave somewhat differ- ently from the A-, B-, and D-bromo-acids, which do not yield lactones when treated in this way. This difference, however, requires confirm- ation before it can be definitely accepted. The D-bromohexahydvo-xylic mid, after complete separation from the C-acid by repeated recrystallisation from light petroleum, melts at about 128-130° and separates from light petroleum, in which it is sparingly soluble in the cold, as a voluminous mass of needles, which completely fill the liquid.It is readily soluble in ether and a solution in this solvent containing 6 grams in 100 C.C. was found, on examina- tion, to be quite inactive. It dissolves readily in dilute sodium carbonate, and on boiling the solution elimination of hydrogen bromide takes place with formation of B-tetrahydro-xylic acid (see next section). An analysis of D-bromo- hexahydro-xylic acid yielded the following results : On analysis : Br = 34.2 C,H,,O,Br requires Br = 34.0 per cent. 0.1896 gave 0.1514 AgBr. Br = 34.1. C,H,,O,Br requires Br = 34.0 per cent.It may, at first sight, seem remarkable that the bromo-acids C and D should show no signs of activity, although the cis-lactones from which they were prepared had a rotation of - 5*3O in a 100 mm. tube. It has, however, already been pointed out that, in the formation of these lactones from camphoric anhydride, racemisation must have taken1388 PERKIN AND YATES: THE ACTION OF ALUMINIUM place, and the fact that the cis-lactones always have a small rotation simply shows that i t has not been quite complete. When the cis-lactones are converted into the bromo-acids and then purified by recrystallisation from light petroleum, the externally com- pensated modifications being less soluble (as is frequently the case) are easily obtained in a pure state, and the traces of the active modifica- tions remain in the mother liquor.That the light petroleum mother liquor of these inactive bromo- acids contains active substances was proved by direct experiment, but the solutions were unfortunately too highly coloured to allow of exact measurements being made. B-Tetrahydro-xylic Acid, C,HI,* C0,H. D-Bromohexahydro-xylic acid dissolves readily in sodium carbonate solution, and if the solution is heated to boiling for a few seconds and then cooled and acidified, an acid separates either at once in the crystalline form, or else as an oil which rapidly solidifies. The solid mass, after drying on a porous plate, melts a t about SOo, and is so soluble in organic solvents that it is difficult to purify it by recrystal- lisation.It crystallises, however, in the form of pearly plates from dilute methyl alcohol, but the operation is rather troublesome, since, unless exactly the right conditions of concentration and temperature have been found, the acid always separates as an oil. D-Tetrahydro-xylic acid melts a t 87', and distils without decomposi- tion; it is almost insoluble in water, but readily volatile in a current of steam. On analysis : 0.1571 gave 0.4020 GO, and 0.1298 H20. C,H,,02 requires C = 70.1 ; H = 9.1 per cent, When left in contact with fuming hydrobromic acid, this acid is rapidly converted into the D-bromohexahydro-xylic acid from which it had been prepared. Oxidation of D-Tetrahydro-xylic Acid-When this unsaturated acid is dissolved in dilute sodium carbonate and mixed with potassium permanganate, the latter is instantaneously reduced, and as it seemed probable that results throwing light on the position of the double linking in this acid (p.1380) might be obtained by studying this oxidation, the following experiment was carried out. The pure acid (5 grams) was dissolved in dilute sodium carbonate mixed with a quantity of powdered ice and oxidised, in a porcelain dish fitted with a turbine, with small quantities of permanganate until the colour remained permanent for 3 minutes. Sodium sulphite was then added to destroy the excess of permanganate, the C = 69.8 ; H = 9.2.CHLORIDE ON CAMPHORIC ANHYDRIDE. PART 11. 1380 liquid heated to boiling, and the filtrate and washings of the manganese precipitate evaporated to a small bulk.The concentrated solution, after acidifying with acetic acid, gave no precipitate with calcium sulphate, showing that no oxalic acid had been formed. The whole was then acidified with hydrochloric acid and distilled in steam to remove a very small quantity of a volatile substance which appeared to be present. The residue in the steam distillation flask was saturated with a.mmonium sulphate, and repeatedly extracted with ether, the ethereal solution was dried over calcium chloride and evaporated, when a pale yellow oil was obtained which, after standing over sulphuric acid in a vacuum desiccator for some days, showed no signs of crystal- lising. It was analysed with the following result : 0.1571 gave 0,3290 CO, and 0.1105 H,O. C9H1,0, requires C = 58.0 ; H = 7.5 per cent.This acid is very readily soluble in water and is monobasic, since 0,207 gram was found, on titration with decinormal caustic soda, to neutralise 0.045 NaOH, whereas this amount of a monobasic acid, C,H1,04, should have neutralised 0.044 NaOH. The remainder of the acid was dissolved in water and oxidised with a slight excess of potassium dichromate and dilute sulphuric acid on the water-bath, the product was then saturated with ammonium sulphate and extracted 20 times with ether. After drying over calcium chloride and evaporating, an oil was obtained which on stand- ing over sulphuric acid became semi-solid; when this was spread on a porous plate, the oily impurity was soon completely absorbed, leaving a hard, crystalline mass which melted roughly at 140'.This crude acid is very soluble in water, but a concentrated solution on standing deposits colourless plates like sugar crystals which, after recrystallisation, melt at 167O with slight previous softening. On analysis : C = 57.1 ; H = 7.8. 0.1121 gave 0,2206 CO, and 0.0704 H,O. C =53*6 ; H= 7.0. C9H,,0, requires C = 53.5 ; H = 6.9 per cent. The new acid is dibasic, since 0.1076 gram required for neutralisa- tion 0.0420 NaOH, whereas this quantity of a dibasic acid, C,H,,05, should neutralise 0.0426 NaOH. It shows all the reactions of a ketonic acid, and when treated with potassium hydroxide and bromine it yields bromoform ; it therefore probably contains the group Me*CO ; unfortunately, the amount of material at our disposal was too small to allow of the isolation and identification of the acid which is formed during this oxidation. These results seem, nevertheless, to indicate the probability of the oxidation of D-tetrahydro-xylic acid proceeding somewhat in the following way VOL.LXXIX. 5 C1390 PERKIN AND YATES: THE ACTION OF ALUMINIUM CMe CMe-OH COMe C H H ~ H , CO(\CH, Q02H\CH2 CHd,)CHMe CH2\!CHMe 07 CH*CO,H CH*CO,H \C/H*C02H D-Tetrah ydro-x ylic Acid, C,H,,04. Acid, C,HI4O, acid. (m. p. 167"). The position of the double-bond in D-tetrahydro-xylic acid has, of course, not been definitely ascertained, and the formula given here has simply been selected to serve as an illustration of the possible mechanism of the oxidation. The Lactone of A- Hydroxyhexahydro-xylic Acid and its Conversion into A-Rromohexahydro-xylic Acid and into A- FetFahydro-xylic Acid.Twenty grams of pure A-hydroxyhexahydro-xylic acid (m. p. 160') were distilled and the distillate dissolved in ether and extracted three times with carbonate of soda to remove traces of an acid which was present (see below). The ethereal solution was then dried over calcium chloride, evaporated and the residual lactone twice fractionated, when practically the whole quantity distilled at 263-265O under 748 mm. pressure the fraction boiling constantly at 264O being collected separately and forwarded t o W. H. Perkin, sen., in order that its specific gravity and magnetic rotation might be determined. This specimen had ft permanent rotation of + 1.96O in a 100 mm. tube. The density and magnetic rotation determinations gave the following results : d 10°/lOo= 1.0640;d 15"/15'= 1.0606 ; d 2Oo/2O0= 1.0575. Density.Magnetic rotation. 15.4" 1.0131 8.174. This trans-lactone has therefore a higher sp. gr. and lower magnetic rotation than the cis-lactones (p. 1383). During its journey by train, it solidified to a hard mass of crystals which although very soluble in light petroleum (b. p. 30-35'), crystallised from this solvent in colourless needles melting at about 5 5 O . t. Sp. rotation. Mol. rotation. On analysis : 0.1963 gave 0.5034 CO, and 0.1641 H20. C,H,,02 requires C = 70.1 ; H = 9.1 per cent. In order to prove that this solid lactone was really the lactone of A-hydroxy~yd~~o-xylic acid, it was warmed with a little baryta water, C = 69.9 ; H = 9.2.CHLORIDE ON CAMPHORIC ANHYDRIDE.PART IT. 1391 in which it very readily dissolved with formation of the barium salt of the hydroxy-acid. The solution was acidified, extracted repeatedly with ether, and tbe ethereal solution, after drying over calcium chloride, evaporated to a small bulk, when crystalline crusts were deposited which melted at 160" and consisted of pure A-hydroxyhexahydro-xylic acid. The lactone of this acid was previously described (this vol., 345) as an oil boiling at 261-264' under 748 mm. pressure, and this specimen showed no signs of crystallising either after standing for 6 months or on cooling in a mixture of ice and salt ; when, however, a crystal of the lactone melting a t 55' was put into the liquid, crystallisation started at once and the whole soon solidified to a hard mass of crystals.The sodium carbonate solution which had been employed in purify- ing the lactone (see above) gave, on acidifying, no precipitate, but it was noticed that after standing for some days a small quantity of needle- shaped crystals had separated. These were collected and dried on a porous plate at the ordinary temperature; they then melted a t SO", and were found to consist of pure A-tetrahydro-xylic acid (see below). It is therefore evident that A-hydroxyhexahydro- xylic acid on distilla tion is almost quantitatively converted into its lactone, but that a very small amount of the acid is decomposed in another direc- tion with elimination of water and formation of A-tetrahydro-xylic acid. A-Bromohexahycho-xyZic Acid.-The lactone of A-hydroxyhexahydro- xylic acid dissolves rapidly and completely in fuming hydrobromic acid (saturated at Oo), but the solution soon becomes cloudy and an oily layer separates which becomes crystalline in a few minutes.After standing for about an hour, the hard, crystalline mass was ground up with water, washed well on the pump, dried on a porous plate a t the ordinary temperature, and then rapidly recrystallised from boiling light petroleum (b. p. 60-70'). The minute, glistening prisms which rapidly separated were analysed, with the following results : 0.1511 gave 0.1121 AgBr. Br=33*9. C,HI,O,Br requires BL = 34.0 per cent. A-Rromohex~~~~dro-xyZ~c Acid melts at about 133' almost without decomposition ; i t is readily soluble in most organic solvents, but only very spariugly so in cold light petroleum ; its solution in ether is in- active.I n appearance and melting point it is so similar to C-bromo- hexahydro-xylic acid that we were a t first inclined to believe in the identity of the two. We therefore mixed equal quantities of the pure substances, and found that the melting point of the mixture was about 100-105° ; i t is therefore clear that the acids are not identical. Considerable quantities of A-bromohexahydro-xylic acid were also prepared by grinding up A-hydroxyhexahgdro-xylic acid with fuming 5 c 21392 PERKIN AND YATES : TEE ACTION OF ALUMINIUM hydrobromic acid. The crystals of the acid become converted into a gummy mass, but this soon solidifies, and after washing well on the pump and drying on a plate, a mass of colourless crystals is obtained which consists Gf the almost pure A-bromo-acid.A-C?~Zoro?~ex~lz?/dl.o-x?/Zic Acid. - When A-hydroxyhexahydro-xylic acid is boiled for a few seconds with concentrated hydrochloric acid, it does not yield the corresponding lactone, but is converted into an oil which, on cooling, solidifies. This was collected, washed well with water, and, after drying over sulphuric acid, rubbed on a porous plate with light petroleum (b. p. 35-40') until free from traces of oil. The colourless, crystalline residue, which was not sufficient for recrystalli- sation, melted at about 92', and, on analysis, gave numbers which showed that it evidently consisted of A-chlorohexahydro-xylic acid : C1= 18.3. CgH,,02C1 requires C1= 18.5 per cent.0.1547 gave 0.1146 AgC1. A-Tetra?tydro-x3lic Acid.-This acid is readily obtained by dissolving A- bromohexahydro-xylic acid in excess of sodium carbonate and boil- ing the solution for a few minutes; it separates on acidifying in an almost pure condition as a colourless, crystalline precipitate. For analysis, it was recrystallised from dilute acetic acid, and thus obtained in the form of colourless groups of needles, which melt at 80' : 0,1587 gave 0.4066 00, and 0.1321 H20. C = 69.9 ; H = 9.2. CgH,,02 requires C = 70.1 ; H = 9.1 per cent. The acid is almost insoluble in cold water ; if, however, it is boiled with water, a small quantity dissolves, and on cooling separates in four-sided plates which melt at 80'; it is readily volatile in steam. Nost organic solvents dissolve i t freely, but it is comparatively sparingly soluble in cold light petroleum (b.p. 35-40'). The acid seems to have no tendency to yield a lactone on boiling with dilute acids ; it separates, for example, unchanged from 20 per cent, sulphuric acid, even after boiling for 5 minutes. When mixed with fuming hydrobromic acid, it becomes soft, but does not dissolve, and from the mixture, after standing for 3 hours, water precipitates a mass of colourless crystals which, after washing with water, drying on a porous plate, and recrystallising from light petroleum, melts at 133', and consists of pure A-bromohexahydro-xylic acid. Oxidation of A-Tetrahydro-xp% Acid.-This acid, when dissolved in sodium carbonate, instantly decolorises permanganate, even at tem- peratures considerably below Oo, and it therefore seemed possible that, by studying this oxidation, results might be obtained which would throw some light on the position of the double bond in the molecule (see p.1380).CHLORIDE ON CAMPHORIC ANHYDRIDE. PART 11. 1393 Six grams of the pure acid were therefore dissolved in dilute sodium carbonate, mixed with powdered ice, and treated with a 3 per cent. solution of permanganate until the pink colour remained permanent €or a t least 2 minutes. The slight excess was then removed with sodium sulphite, the whole heated t o boiling, filtered, and the filtrate and washings of the man- ganese precipitate evaporated t o a small bulk and tested for oxalic acid, but no trace of this acid could be detected. After acidifying and extracting repeatedly with pure ether, the ethereal solution was dried over calcium chloride and evaporated, when a thick, brownish, oily acid was obtained, which mas left over sulphuric acid in a vacuum desiccator for 4 days and then analysed, with the following result : 0.1254 gave 0.2622 CO, and 0.0887 H,O.C,H,,O, requires C = 58.0 ; H = 7.5 per cent. This acid is readily soluble in water, and is evidently ketonic in character, since its aqueous solution gives at once a yellow, oily pre- cipitate with phenylhydrazine acetate. That i t is monobasic is shown by the results of the titration with decinormal sodium hydroxide, when 0,2366 gram required for neutralisation 0.0508 gram NaOH, whereas this quantity of a monobasic acid, CgHl4O4, should neutralise 0.0509 gram NaOH.We next oxidised this acid with potassium dichromate and dilute sulphuric acid, exactly as described in the case of the isomeric acid from D-tetrahydro-xylic acid (p. 1389), and on extracting the product with ether, an oily acid was obtained which did not crystallise even after standing over sulphuric acid in a vacuum dcsiccator for some weeks. This oil gives an oily precipitate with phenylhydrazine acetate, and yields bromoform in considerable quantity when treated with bromine and potassium hydroxide ; i t is, therefore, evidently a ketonic acid, but as it did not solidify it was not further investigated. C = 57.0 ; H = 7.9. Pownation of B-Bro.nzohexcciLydro-xylic Acid ayhd of B-9?etmJyd~*o-x~Zic Acid from the Lccctone of B-H~droxyhexuI~~dl.o-x?llic Acid. The lactone used in these experiments was prepared by distilling the pure B-hydroxy-acid as described in the previous communication, it boiled a t 258-260' under 745 mm.pressure and melted a t 44'; i t WRS particularly noticed t h a t even after repeated distillation there was no appreciable alteration in the melting point, clearly proving that even a t the high temperature of the distillation, no change into a cis- modification takes place. When this lactone is melted and mixed with three times its volume of fuming hpdrobrornic acid (saturated at OO), it dissolves, but the solution suddenly becomes opaque and an oil1394 PERKIN AND PATES: THE ACTION OF ALUMINIUM separates which begins to crystallise a t once, the change from B-lactone to crystalline bromo-acid being apparently even more rapid than when the A-lactone is similarly treated (p. 1391).The product was mixed with water, the crystals collected, allowed to dry on a porous plate at the ordinary temperature, and then crystallised from light petroleum (b. p. 60-70O). On analysis : 0°1520 gave 081212 AgBr. Br = 33.8. C,H,,O,Br requires Br = 34.0 per cent. B-Bromohexahydro-xylic Acid melts at about 1 2 8 O with decomposition, and is more readily soluble in light petroleum than the corresponding A-acid. It dissolves easily in sodium carbonate, and if the solution is boiled for a few minutes, then cooled and acidified, a crystalline pre- cipitate separates which, after crystallising from dilute acetic acid, melts at about 6s' and consists of B-tetrahydro-xylic acid.0.1592 gave 0.4078 CO, and 0.1303 H20. C = 69.9 ; H e 9.1. C9H,,0, requires C = 70.1 ; H = 9.1 per cent. B-TetvaRpdro-xglic Acid is very spnringly soluble in cold water, but it may be crystallised from large quantities of boiling water ; its solu- tion in sodium carbonate instantly decolorises permanganate. When left in contact with fuming hydrobromic acid, it becomes soft but does not dissolve, and if after 2 hours water is added, a white, crystalline precipitate separates which crystallises from light petroleum in woolly needles melting at 1 2 8 O and consisting of pure B-bromohexa- hydro-xylic acid. CHMe A'-~%trahyd~o-zy/lic Acid, CH,/\CH CHI ICHhe, and its conversion into \/ C*CO,H CHMe 2-Brorno~~excchydro-xgl~c Acid," CH2f)gg%Ie , ccnd into Xplic Acid.CHBr\/ CH*CO,H Al-Tetrahydro-xylic acid is structurally isomeric with the tetra- hydro-xylic acids, A, B, and D, and is the acid which is formed when * The only other formula: possible for these acids are : CHMe CHMe CH,/'\CH, I I and CH,\//CMe CTO,H CH *CO,HCHLORIDE ON CAMPHORIC ANHYDRIDE. PART 11. 1395 x y h acid is reduced with sodium and isoamyl alcohol, and when methyl a-bromohexahydro-xylate is hgdrolysed with alcoholic potash (Bentley and Perkin, Trans., 1897, 71, 173 ; Lees and Perkin, this VO~., 338), it melts at 107'. When it is mixed with fuming hydro- bromic acid, it does not readily dissolve, but the crystals are seen to undergo gradually a change in appearance. I n order to ensure the reaction being complete, the mixture was sealed up in a tube and shaken from time to time, and after two days water was added, the crystals collected on the pump, and allowed to dry on a porous plate in contact with air. The substance then melted at about 124-125', but after crystallising from light petroleum (b. p. 50-60°), colourless, glistening prisms were obtained which melted a t 127' without decom- position. On analysis : 0.152 gave 0.1208 AgBr. Br = 33-8. C,H,,O,Br requires Br = 34.0 per cent. When treated with sodium carbonate, ~-bromoTLexuT~ydro-xylic acid shows quite a different behaviour from that observed in the case of the A, B, and D-bromohexahydro-xylic acids (pp. 1388, 1392,1394). It dissolves at first in the sodium carbonate, forming a clear solution which then rapidly becomes cloudy, and an oil separates which is very readily volatile in steam, smells like a hydrocarbon, and is evidently tetrahydro-mxylene. C',H,,O,Br = CsHla+ HBr + GO,. After boiling until the hydrocarbon was expelled, the clear solution gave on acidifying a colourless, crystalline precipitate which, when drained on a tile and dried at go', melted sharply at 107-108*, and evidently consisted of Al-tetrahydro-xylic acid. Actiori of Xdphwic Acid on A1-Tetrahydyo-xylic Acid.-This acid dissolves in concentrated sulphuric acid, and when the solution is heated at 100° for 10 minutes, sulphur dioxide is rapidly evolved and the dark coloured liquid, on dilution with water, deposits a yellow, crystalline precipitate. This was collected, distilled, and recrystallised from dilute acetic acid, when colourless crystals were obtained which melted a t 124' and consisted of xylic acid. It is therefore evident that, in its behaviour with hydrobromic acid and with sulphuric acid A*-tetrahydro-xylic acid shows the greatest similarity to the A, B, and D tetrahydro-xylic acids described in this paper. I n conclusion we wish to express our thanks to Professors F. S. Kipping and W. J. Pope for many valuable suggestions that they were good enough to make during the course of this research.1396 GILBODY, PEKKIN, AND YATES : We also wish to state that the cost of the large amount of material which was required in this research has been to a large extent defrayed by repeated grants from the Government Grant Fund of the Royal Society. THE OWEXS COLLEGE, MANCHESTER.

ISSN:0368-1645    

DOI:10.1039/CT9017901373

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

1396 GILBODY, PEKKIN, AND YATES : CXLV1.-Brazilin and Hamatoxylin. Part 1. By A. W. GILBODY, W. H. PERKIN, jun., and J. YATES. BRAZIL-WOOD, or Red-wood, which was originally imported from the East Indies, has been used in Europe for dyeing purposes from very early times and certainly before the discovery of America. Thus, about the year 1190, the Spanish writer Kimichi mentions dye- woods called B r e d or Brasil (from b*axcc, fiery-red), and when the Spaniards discovered South America in 1500, it is probable that they named the northerly portion Brazil, after the dye-wood which is found there in such immense quantities. The Brazil-wood tree belongs to the Leguminosccz, species Ccesalpinia, and is widely distributed in the Tropics, in the East Indies, South and Central America, the Antilles, and Africa.The most valued Brazil-wood (Fernambukholz, bois de Fernambouc) is obtained from Ccescdpinio Crista and C. brasiliensis, large crooked trees, with knotty stems, which occur in great numbers in the forests of Brazil and Jamaica. The wood, which comes into the market in round blocks, is very hard and of a deep red colour ; when freshly cut, the colour is light yellow, but this rapidly changes to red in contact with the air. The crude material is rasped and extracted, either by simply boiling with water, ,or by heating with water under pressure, the liquid is then con- centrated in vacuum pans, the actual extract sent into the market varying very much in strength. Brazil-wood extract is still used in dyeing, but to a comparatively limited extent, owing t o the fugitive character of the colours which it yields.It is fixed on the fibre usually in the form of its aluminium or tin lakes, which, although less brilliant and fast than the correspond- ing alizarine lakes, are somewhat similar to these in appearance. Bmxilin, the actual colouring matter of Brazil-wood, of ten separates from the commercial extracts in the form of dark brown, crystalline crusts, and pure brazilin is comparatively easily obtained from this crude material by repeated recry stallisation from water containing a small quantity of sulphurous acid, from which solution i t separates in pale yellow prisms. The first chemist to isolate braxilin in a crystal-BRAZILIN AND HAMATOXYLIN. PART I. 1397 line form appears to have been Chevreul (Ann.Chiin., 1808, [i], 66, 225), but no attempt was made to determine its constitution until Bolley (Schweix. polyt. Zeitsch., 1864, 9, 267) suggested the formula C,,H,,07, as the result of several analyses ; Kopp (Be?.., 1873, 6, 446) subsequently repeated the analyses and considered the formula C2,H1,07 as more probable. It was, however, left to Liebermannand Burg (Be?.., 1876, 9, 1883) to determine accurately the composition of brazilin, and the formula, CI6Hl4O5, which they proposed is that which is used at the present day. The first important step which afforded any evidence of the constitution of brazilin is due to Kopp (Zoc. cit.), who showed that when submitted to dry distillation, this sub- stance yields, besides tar, considerable quantities of resorcinol and, indeed, the yield is so good that this method mas for a long time used for its preparation.Before this, Bolley (Zoc. cit.) had treated brazilin with nitric acid and obtained a yellow substance which he imagined to be picric acid, but which Reim (Ber., 1871, 4, 334) subsequently showed was trinitroresorcinol or styphnic acid, C,H(NO,),(OH),. A t a somewhat later date, Liebermann and Burg (Zoc. cit.) showed that resorcinol is also produced in quantity when brazilin is fused with potash, and thus i t was early recognised that brazilin is a deriv- ative of resorcinol. The same chemists also proved that brazilin contains four hydroxy-groups, since when treated with acetic anhydride it is converted into a crystalline, colourless, tetracetgl derivative, C,,Hl,0(OAc)4.This was subsequently confirmed by Dralle (Ber., 1884, 17, 375) who, by treating brazilin with sodium methoxide and methyl iodide, obtained t?.inzet~~~ZbrccxiZin, C,,Hl,O(OMe),*OH, a substance which still contains a hydroxyl group, since it yields an acetyl compound and when heated in benzene solution with sodium and methyl iodide a t 120’ is converted into tetrametl~glbraxizi~, C,,H,,O(OMe),. Of the four hydroxy-groups in brazilin, three are therefore easily methylated, whereas the fourth is not ; for this reason it was assumed that whereas the three are aromatic or phen- olic, the fourth is alcoholic, and a further examination of the properties of brazilin has shown that this assumption is correct. When brazilin is oxidised, it loses two atoms of hydrogen and is converted into braxdein, This change takes place under various conditions; thus Liebermann and Burg (Zoc.c i t . ) obtained crude brazilein by exposing an alkaline solution of brazilin to the air and by treating an alcoholic solution of brazilin with iodine. Hummel and A. G. Perkin (Be?*., 1882, 15, 2343) prepared pure crystalline brazilein by passing air through a solution of brazilin in ammonia. Buckha and Erck (Bev., 1884, 171398 GILBODY, PERKIN, AND YATES: 685 ; 1885, 18, 1140) obtained brazilein by oxidising brazilin with small quantities of nitric acid, and Schall and Dralle (Be?*., 1890, 23, 1433) by treating its solution in glacial acetic acid with sodium nitrite, If air is passed through a solution of braailin in dilute alkali for a considerable time, the purple colour of the solution gradually changes to a reddish-brown and the brazilein which is first produced is corn- pletely oxidised.Schall and Dralle (Ber., 1888, 21, 3017 ; 1889, 22, 1559; 1892, 25, 19), who first studied this oxidation, isolated from the product P-resorcylic acid, OH/\OH \/ I lCOzH' and a substance, C,H,O,, which crystsllised in needles melting a t 271" and contained two hydroxyl groups, since it yielded a diacetyl compound, C9H4O,( OAC)~, and a dimethyl ether, C9H4O2(0Me),. This dimethyl ether, on treatment with acetic acid and perman- ganate, is oxidised to p-methoxysalicylic acid, CGH,(OMe)(OH)*CO,H, and on this account and also because the substance CSHGO, does not combine with hydroxylamine or phenylhydrazine, they first assigned t o it the constitution OH{ OH $)7?-->0 ,)-+a3 Schall (Ber., 1894, 27, 528) afterwards suggested that this sub- stance, C,H,O,, might possibly be a phenyl-y-pyrone derivative of the for mula 0 and this view was subsequently proved by Feuerstein and Kostanecki (Ber., 1899, 32, 1025) to be correct.These chemists showed that when the dimethyl ether of this sub- stance is boiled with sodium ethoxide it is converted into fiseto€ dimethyl ether (Herzig, Monatsh., 1891, 12, 187) with elimination of formic acid, a decomposition which is evidently represented thus : Dimethyl ether of C,H,OI. Fisetol dimethyl ether.BRAZILIN AND HBMATOXYLIN. PART 1. 1390 This proof of the constitution of the substance C,H,O,, taken in connection with the results which had been obtained by Herzig (Mo~zc~tsl~, 1898, 10, 738) and by us (see below) led Feuerstein and Kostanecki (Zoc. cit., p.1028) to suggest the formula 0 as probably representing the constitution of brazilin. Oxidation of yrimeth y&adin with Potassium ~ermanganale. During the course of a long series of experiments on the con- stitution of brazilin and haematoxylin which have been in progress since 1883 and some of the resultsof which have 1a.tely been published as abstracts in the Proceedings (1899, 15, 27, 75, and 241 ; 1900, 16, 105 and 107), we have carefully studied the behaviour of trimethyl- brazilin, ClGH1,O,(OMe),, with permanganate under very varied con- ditions. We obtained in this way, besides -oxalic, acetic, and formic acids, the following important oxidation products, the investigation of which has thrown much light on the problem of the constitution of brazilin. A.An acid of the formula C19H1809, m. p. 208'. B. 9 9 C. D. 9 ) 9 9 C12H120f3, 9 9 lZ9 * I n the present paper, the description and determination of the con- stitution of the acids B and C are given in detail, the investigation of the acids A and D, called brazilinic and brazilic acids respectively, and their decomposition products is not yet complete and will form the subject of a future communication. Examination of the Acid B of the Formula Cl0HlOO6 and Melting Point 1744-This acid crystallises from water in long needles ; it is dibasic, since it yields a silve?* salt, CIoH,OGAg,, it contains one methoxy-group, and when fused with potash is decomposed with formation of a substance which, since it gives with ferric chloride an intense violet coloration, is probably a derivative of resorcinol.When the aqueous solution of this acid is heated with water at ZOO0, carbon dioxide is eliminated and a monobasic acid, C,H,,O, (m. p. 118"), is produced, and this pehaviour, taken in conjunction with the fact that brazilin under various conditions yields p-methoxy-1400 GILBODY, PERKIN, AND YATES : salicylic acid, suggested to us that the constitutions of the two acids, C,oH1oO, and C9H1004, are very probably represeuted by the formulae, OMe()OCH,*CO,H \/ 2-Carboxy~5-methoxyphenoxy- acetic acid. m-Methoxyphenox y - acetic acid. In order to prove these formulae, we determined to attempt the synthesis of the acid C9H,,04 and ultimately succeeded in doing this by treating the sodium compound of resorcinol monomethyl ether with ethyl bromoacetate. OMe/\ONa + Br*CH,*CO,Et = OMe/\O*CH,*CO,Et.I I I I \/ \/ The m-met~oxy~henox?/acetic acid, which was obtained by hydrolysing the product, melted a t 118' and was identical with the acid C,HIoO, produced by heating the acid Cl,Hl,06. There can t,herefore be no doubt that the latter is 2-curboxy-5-methoxyp?~enox~acetic acid and has the constitution represented by the formula given above. Examination of the Acid C of the Pornaula C,,H,,O, and of Melting Point about 195*.-This acid crystallised from its dilute aqueous solu- tion in flat prisms containing 2 mols. of water of crystallisation and from concentrated solutions it separated in long, thin needles which were anhydrous.It is a dibasic acid, yielding a silver salt, cloH,O,Ag,, and an anlqdride melting at 1 7 5 O . When heated with hydrochloric acid a t 180', it was completely decomposed into carbon dioxide and catechol, and since it contains two methoxy-groups, its constitution must be represented by one of the formulae C0,H OMe/)CO,H O M e A C 0 , H OMe!!, OMc()CO,H Hemipinic acid. m-Hemipinic acid. Since the melting points, or rather the decomposing points, of these two acids depend so much on the rapidity with which the determina- tion is made and the anhydrides melt a t approximately the same tem- peratures, advantage was taken of the wide difference in the melting points of their ethylimides, (OMe),C,H,( CO),NEt, in order to dis- tinguish between them.Goldschmiedt (Monatsh., 1888, 0, 339) first showed that whereas the ethylimide of hemipinic acid melts at 98", the corresponding derivative of m-hemipinic acid does not melt until 230'. Experiment showed that the ethylimide of the acid from tri-BRAZILIN AND HEMATOXYLIN. PART T. 1401 methylbrazilin melted at 230' and therefore there can he no doubt that this acid is m-hemipink acid. The isolation of m-hemipinic acid and of catechol from the products of the oxidation of trimethylbrazilin is a result of great importance, since it proves that braailin, besides being a resorcinol derivative, also contains a catechol nucleus. It should be mentioned, however, that shortly before the publication of this result (Proc., 1899, 15, 27), Herzig (Monatsh., 1898, 19, 738) had shown that when brazilin is fused with potassium hydroxide it yields a small quantity of an acid which he identified by its melting point and colour reaction with ferric chloride as protocatechuic acid, so that he was actually the first to discover that brazilin is a derivative of cat ec h 01, The Constitution of Bradin.The isolation of 2-carboxy-5-methoxyphenoxyacetic acid and m-hemi- pinic acid from the products of the oxidation of trimethylbrazilin not only proves that brazilin contains both resorcinol and catechol nuclei, but the structure of these acids also affords most valuable evidence as to the way in which these two nuclei are linked together. If the formuIa?. of the two acids are written side by side without their methyl groups, \/\OH 0 *CH,* C0,II C0,H I [OH' OHf\l' v \ C O , H C0,H' it is clear that in the formula of brazilin these two nuclei must be united in the positions indicated by the dark lines.If now the skeleton formulae of these two acids be written thus, i t is at once evident that in constructing a constitutional formula for brazilin, Cl6Hl4O5, these two residues, which contain C17, must be fused together in such a way that one carbon atom iscommon to both. Since it is known that in the centre portion, between the two nuclei, brazilin contains an alcoholic hydroxy-group, it seems to us that there can hardly be a doubt t h a t one of the two following formulae repre- sents the constitution of this substance. I. 11.1402 GIILBODY, PERKIN, AND PATES : It is obvious that neither formula 111, first proposed by Gilbody and Perkin (Proc., 1899, 15, 75), nor formula IV, suggested by Feuerstein and Kostanecki (Ber., 1899, 32, l02S), 0 0 OH m.IV. can possibly represent brazilin, since neither of these gives any explanation of the formation of 2-carboxy-5-methoxyphenoxyacetic acid or of m-hemipinic acid by the oxidation of trimethylbrazilin. On the other hand, both formulze I and I1 not only account in a satis- factory manner for the formation of these acids, but they are also in agreement with all the other :properties of brazilin which are known at the present time. The new formulze, I and 11, represent brazilin as a derivative of a t e t r u h y d r o p ~ ~ e n o - ~ - p ~ ~ ~ ~ ~ e of the formula 0 a group of atoms that does not appear to have been met with in any of the natural colouring matters hitherto investigated. These formulae for brazilin are, nevertheless, very similar to those of some of the natural colouring matters and bear considerable resemblance especially t o that of fisetin which Herzig (Nonatsh., 1894, 15, 688) and Kostanecki (Ber., 1895,28,2302) have shown to have the constitution 0 Herzig (Monatsh., 1901, 22, 209) has lately expressed the opinion.that although the formation of 2-carboxy-5-methoxyphenoxyacetic acid and m-hemipinic acid from trimethylbrazilin practically proves the position of all the carbon atoms in the molecule, there is still no actual proof of the existence of a y-pyrone ring in brazilin. Since, however, Feuerstein and Kostanecki (Zoc.cit.) have conclusively proved that the substance C,H,O, obtained by Schall (Zoc. cit.) by passing air through an alkaline brazilin solution is a pheno-y-pyrone derivative of the formulaBRAZILIN AND HEMATOXYLIN. PART I. 0 1403 it appears t o us that t.here can scarcely be a doubt that brazilin itself also contains a y-pyrone ring. As soon as it has been decided which of the formulse I or I1 is too be accepted as representing brazilin, Cl6Hl4O5, the probable constitution of brazilein, C,,H,,O,, may be deduced by assuming that the two hydrogen atoms which are removed in the conversion of the former into the latter are derived from the CH-OH group and the hydroxyl group of the resorcinol nucleus. If formula I be taken aB an example, the formula of brazilein deduced in this may mould be 0 This relationship between brazilin and brazilein can, however, not be considered proved until i b has been found possible to reconvert the latter into the former by reduction.Preparation of TrimethyZbs*uziZin, C,,H,,O,(OMe),. The trimethylbrazilin required for this research was prepared by Schall and Dralle's method (Bet-., 1888, 21, 3009), but during the course of the preparation of several kilos. of the substance we found i t advantageous to introduce slight modifications into the process, which we now conduct as follows. Brazilin (143 grams) is dissolved in the smallest possible quaatity of hot absolute methyl alcohol, and mixed in a large flask connected with a reflux apparatus, with a solution of sodium (35 grams) in methyl alcohol, an operation which causes the separation of a mass of crystals, consisbing probably of the trisodium compound of brazilin. A slight excess of methyl iodide (250 grams) is then added and after well mixing, the flask is immersed in a large water-bath and heated at 60-65" day and night for 50 hours, the temperature being kept constant by a regulator and access of air avoided as far as possible by inserting a stopper of cotton wool into the open end of the condenser.The product is poured into about 6 litres of water, allowed to stand for 24 hours, and the precipitate, after collecting on the pump and washing with water, is transferred to large flasks and extracted with warm ether until all the trimethylbrazilin has been dissolved. The ethereal1404 GILBODY, PERKIN, AND YATES : extract is shaken repeatedly with sodium hydroxide, dried over calcium chloride and evaporated to a small bulk, when on standing and even during the concentration, the trimethylbrazilin separates as a pale yellow, crystalline mass, which after washing on the pump with ether is almost pure and in this condition was used in all our experiments. During the extraction of the crude trimethylbrazilin with ether, the impurities first dissolve, the mass becomes more and more sparingly soluble, and ultimately a peculiar, brownish-violet residue is obtained, which closely resembles amorphous phosphorus in appear- ance and is apparently quite insoluble in ether.Although somewhat tedious, the purification with ether is much to be preferred, as the alternative method, namely, crystallisation from alcohol, is more wasteful and frequently does not give at once so pure a product.The yields we obtained usually from 1 kilo. of brazilin were 950 grams of crude product, which on extraction with ether yielded about 700 grams of trimethylbrazilin and 60 grams of the brownish-violet, insoluble residue, the remainder consists largely of dimethylbrazilin which is dissolved out during the treatment of the ether extract with sodium hydroxide, and partly of uncrystallisable resins remaining in the ethereal mother liquors of the trimethylbrazilin. A specimen of trimethylbrazilin which had been purified by recrys- tallisahion from ether was analysed with the following results : 0.1612 gave 0-4102 CO, and 0.0888 H,O.C16Hl102(OMe)3 requires C = 69.5 ; H = 6.1 per cent. A methoxyl determination by Zeisel's method gave the following 0.2121 gave 0.4631 AgI. OCH, = 29.1. C = 69.4 ; H = 6.1. result :- ClsH,,02(0Me), requires OH, = 28.2 per cent. Oxidation of Tv+mthylbmzilin wit?& Potassium Permccrzganate. When ground up into a fine paste with water, trimethylbrazilin is slowly attacked at the ordinary temperature by permanganate and in our earlier experiments much material was oxidised in this way. A long series of comparative trials showed, however, that there was not much difference in the yield of acids produced a t 15' and a t 90°, and as oxida- tion is much more rapid at 90°, we have during the last two years worked almost entirely at this temperature. The oxidation is now carried out as follows.Trimethylbraailin (10 grams) is ground up into an exceedingly fine paste with a little water, washed into a 4-litre flask with about 500 C.C. of hot water, and a cold saturated solution of potassium permanganate added in small quantities at a time, with re- peated shaking, the flask being heated during tho whole operation onBRAZILIN AND HBMATOXYLIN. PART I. 1405 the water-bath. As soon as the colour of the permanganate remains permanent for several minutes (which is the case after about 18 hours), the excess is destroyed by the addition of a little sodium sulphite, and the whole filtered on the pump by means of a Buchner funnel. The manganese precipitate is ground up with hot water and filtered again, and, after repeating this operation, the washings are added to the original filtrate, the whole nearly neutralised with hydrochloric acid and evaporated to a small bulk, first in an enamelled basin over the free flame and then on the water-bath.During this operahion, a small quantity of a crystalline precipitate is usually deposited ; this was collected and found to consist of un- changed trimethylbradin. On acidifying the cold, slightly brownish- coloured liquid with hydrochloric acid, i t becomes pink and deposits a red, resinous precipitate. This is extracted repeatedly with small quantities of chloroform. The chloroform solution is then dried over calcium chloride and evaporated, and the reddish-brown, resinous resi- due, which contains bmzilinic acid and braxilic a d , treated as described on p.1410. The aqueous solution, which had been extracted with chloroform, is saturated with ammonium sulphate and extracted at least 20 times with ether. The ethereal solution is then dried over calcium chloride and evaporated to a small bulk, when, on standing, it deposits a yellow, crystalline precipitate, which consists almost en- tirely of m-hemipinic acid and 2-carboxy-5-methoxyphenoxyacetic acid. OMef )CO,H Im-Hemipinic Acid, OMe,,CO,H The crude mixture of m-hemipinic acid and 2-carboxy-5-methoxy- phenoxyacetic acid, obtained as just described, was recrystallised once from water with the aid of animal charcoal and then distilled under 55 mm. pressure, when almost the whole quantity passed over a t 1 7 2 O as a yellow oil, which, on cooling, solidified and consisted of a mix- ture of m-hemipinic anhydride and 2-carboxy-5-methoxyphenoxyacetic acid.It was dissolved in the smallest possible quantity of boiling toluene and the crystals which separated on cooling and those ob- tained by concentrating the toluene filtrate, were finely powdered and extracted repeatedly with small quantities of dilute sodium carbonate. The insoluble m-hemipinic anhy&ide was then crystallised from toluene, from which it separated in pale yellow crystals melting a t 175'. On analysis : 0,1661 gave 0.3521 CO, and 0.0607 H,O. This anhydride dissolves readily in dilute methyl alcoholic potash, VOL. LXXIX. 6 D C = 57.8 ; H = 4-0. C,,H,O, requires C = 57.7 ; H = 3.8 per cent.1406 GILBODY, PERKIN, AND YATES : and if the solution is evaporated until free from the alcohol and then acidified, a woolly mass of needles separates, which, after washing with a little water on the pump, consists of pure m-hsmipinic acid.On analysis : 0.1 168 gave 0.2272 CO, and 0,0481 H20. A methoxpl determination by Zeisel's method furnished the follow- 0.3457 gave 0.6890 AgI. OCH,= 26.3. (OCH,),C,H2(C02H)2 requires OCH, = 27.4 per cent. The pure ma-hemipinic acid obtained in this way, when moderately rapidly heated, softens a t 190° and decomposes quite sharply at 194-195O into water and the anhydride, but other specimens pre- pared during this research, which had not been purified by conversion into the anhydride, showed a lower and much less sharp melting or de- composing point ; according to Goldschmiedt (Monatsh., 1885, 8, 380), m-hemipinic acid melts when rapidly heated a t 179-182', and as there is thus a slight discrepancy in the melting points, it became necessary to sharply characterise the acid from brazilin.In the first place, it was repeatedly noticed that the latter acid has the property of crystallising in two entirely different ways, thus, when it separates rapidly from a strong solution in hot water, it is obtained in needles'which are anhydrous, but if its saturated aqueous solution is allowed to evaporate at the ordinary temperature, glistening prisms are deposited which contain 2 mols. of water of crystallisation, as the following determination shows : C = 53.0 ; H = 4.5. C10H,,06 requires C = 53.1 ; H = 4.4 per cent. ing result : 0.4371, Itt looo, lost 0.0596 H,O H,O= 13.8.CIoHlo06,2H,0 requires H,o = 13.7 per cent. This capability of crystallising in two such distinct forms is one of the characteristics of m-hemipinic acid. m-Hemi~'netl~~Z/limide, (OMe),C,H,(CO),NEt.-In order to be quite certain that the acid was mhemipinic acid, a small quantity was dis- solved in water, made strongly alkaline with ethylamine, evaporated to dryness, and the residue distilled from a small retort. The yellow, crystalline distillate separated from alcohol, in which it is very sparingly soluble, in yellow needles melting at 230' and consisted of pure m-hemipinethylimide. On analysis : 0.2241 gave 11.9 C.C. nitrogen at 19' and 757 mm. Goldschmiedt gives 230' as the melting point of the ethylimide of N = 6.1. C1,H1,O,N requires N = 5.9 per cent.the m-hemipinic acid which he obtained from papaverine.BRAZILIN AND IIXMATOXYLIN. PART I. 1407 Formation of Catachol fi*oin m-liemipinic Acid 69 t?g Action of Hp?rochloric Acid.-This experiment was carried out before it was known that the acid obtained from trimethylbradin was m-hernipinic acid. The pure acid (2 grams) was heated in a sealed tube with con- centrated hydrochloric acid at 185' for an hour, when on opening the tube there was considerable pressure, and the gas which escaped burnt with a green edged flame and was doubtless methyl chloride, This gas also contained carbon dioxide, as was shown by leading it through baryta water. The contents of the tube were filtered from a few black specks, the filtrate extracted 10 times with ether, and the ether evapa- rated, when an oily residue was obtained, which on standing over sixlphuric acid crystallised in large plates. The crystals were left in contact with a porous tile until quite dry and recrystallised from benzene with the aid of animal charcoal ; the colourless prisms thus obtained were analysed : 0.1671 gave 0.4012 CO, and 0.0830 H,O.C = 65.5 ; H = 5.5. CGHG02 requires C = 65.5 ; H = 5.5 per cent. This substance melted at 104-105O and its solution in water gave with ferric chloride an intense green coloration, which on the addition of ammonium carbonate became first violet and then red. There can be no doubt that it is catechol, since a small quantity mixed intimately with an equal weight of a pure sample of catechol melted at 104'.It is therefore clear that m-hemipinic acid, when heated with hydrochloric acid at 185", is decomposed according to the equation (ONe),C6H,(CO2H), + 2HCl= CGH,(OH), + 2C0, + 2MeC1. This decomposition had not previously been observed, and it is certainly remarkable that the two carboxyl groups attached to the benzene nucleus should be so easily and completely removed at this comparatively low temperature. When hemipinic acid is heated with hydrochloric acid at 1 70", i t behaves differently, protocatechuic acid being produced by the elimination of only one carboxyl group. OMe /\O*CH,*CO,H 2-Carboxyd-met?~oxyp?~e~zox~ucetic Acid, I ICO,H \/ The sodium carbonate solution, which had been separated from the m-hemipinic anhydride as described on p. 1405, gave, on acidifying, a crystalline precipitate, which mas collected and purified by recrys- tallisation from water, from which it separated in long needles.On analysis :1408 GILBODY, PERKI,N, AND PATES : 0.1469 gave 0.2863 CO, and 0.0603 H,O. C = 53.1 ; H = 4.5. 0.1912 ,, 0,3736 CO, ,, 0.0777 H,O. C=53*1 ; H= 4.4. CloH1,O, requires C = 53.1 ; H = 4.4 per cent. 2-Curbox~-5-rnethoxyphenoxyacetic acid melts at about 174" and seems to have no tendency to form an anhydride, as is shown by the fact that even on distillation it passes over unchanged. It is very sparingly soluble in cold water, but dissolves readily on boiling; it is also sparingly soluble in ether, benzene, or light petroleum, but readily so in methyl alcohol, acetone, or warm acetic acid; from the last of these solvents, it separates on cooling in beautiful, colourless needles.When fused with potassium hydroxide, a product is obtained which, on acidifying and extracting with ether, yields a substance which gives the resorcinol reaction with ferric chloride, and this experiment was the first which afforded us any clue to the constitution of the acid. A determination of the methoxyl group by Zeisel's method was made, with the following result : 0.3784 gave 0,4133 AgI. OCH, = 14-40. CH3*O*C6H,(O~CH2*C0,H)*C02H requires OCH, = 13-72 per cent. That this acid is dibasic was shown by titration with decinormal sodium hydroxide, when 0.2005 gram of the pure acid required for neutralisation 0.0708 gram NaOH, whereas this amount of an acid, C,,H,,O,, if dibasic, should neutralise 0.0709 gram NaOH.The salts of 2-carboxy-5-methoxyphenoxyacetic acid are sufficiently characteristic to be described in some detail. The silvey salt, CloH,0,Ag2, is obtained as a white, gelatinous pre- cipitate on adding silver nitrate to a slightly alkaline solution of the ammonium salt. On analysis : 0,2565 gave 0.2538 CO,, 0.0466 H20, and 0.1252 Ag. C = 27-0 ; H = 1.9 ; Ag = 48.8. C,,K,O,Ag, requires C = 27.3 ; H = 1 *8 ; Ag = 49.1 per cent. A slightly alkaline solution of the ammonium salt showed the fol- lowing characteristic behaviour with reagents : Calcium Chloride gives, in a moderately concentrated solution, a white, amorphous precipitate, which dissolves in warm water, but on boiling separates out again as a very sparingly soluble, amorphous substance.I n weaker solutions, calcium chloride gives no precipitate in the cold, but the amorphous calcium salt separates on boiling. Barium Chlom'ds gives a white, amorphous precipitate which, on warming with water, dissolves, but when the solution is boiled, a very sparingly soluble salt separates in microscopic groups of needles. Copper Xulphccte gives no immediate precipitate i n the cold, but, onBRAZILIN AND HBMATOXYLIN. PART I. 1409 standing, an insoluble copper salt slowly separates in pale blue needles ; the separation takes place a t once on boiling the solution. Zinc SuZplmte.-When this reagent is added to a moderately strong solution of the ammonium salt, the solution remains clear for a few seconds and then suddenly becomes cloudy, owing to the separation of an amorphous zinc salt.If a weak solution is mixed with zinc sul- phate and allowed to stand, the zinc salt separates slowly in groups of spherical individuals, which, seen under the microscope, closely resemble yeast cells. Magnesium Chloride gives no precipitate in the cold, but on boil- ing, a sparingly soluble salt gradually separates in four-sided plates. m-Methox yphenox yacetic Acid, MeO()O*CH,*CO,H v When 2-carboxy-5-methoxyphenoxyacetic acid is heated in a sealed tube with water at 200-210° for 2 hours, decomposition takes place and on opening the tube carbon dioxide escapes. The solu- tion, which is nearly colourless, but contains carbonaceous specks in suspension, is filtered, concentrated, and allowed to stand, when crystals gradually separate, which are purified by recry stallisation from water.On analysis : 0.1 192 gave 0.2589 GO, and 0.0584 H,O. C = 59.2 ; H = 5.4. 0.187 ,, 0.4059 00, ,, 0.0917 H,O. C=59*2 ; H=5.5. C,H,,,O, requires C = 59.3 ; H = 5.5 per cent. m-Methoxyphenoxyacetic acid softens at 115' and melts at 118' ; it is only sparingly soluble in cold, but dissolves readily in hot, water. It has a great tendency to separate from its hot aqueous solution, on cooling, in oily drops, which take some time to solidify, but this may be avoided by keeping the solution moderately dilute and stirring continually with a glass rod on the sides of the beaker during cooling ; it is then obtained iu the form of slender needles. Synthesis of m-Methoxyphenoxyacetic Acid.-In carrying out this synthesis, 25 grams of resorcinol monomethyl ether, OMe*C,H,*OH, which had been carefully freed from all traces of resorcinol by repeated fractional distillFtion, were dissolved in alcoholic sodium ethoxide (con- taining 5 grams of sodium), and the solution mixed with 35 grams of ethylic bromoacetate.On heating this mixture in a reflux apparatus on the water-bath, decomposition set in at once, and, after heating for 2 hours, water was added, the whole extracted with ether, and the ethereal solution well washed until free from alcohol, dried over calcium chloride, and evaporated. The oily residue, after twice fractionating under reduced pressure, boiled constantly a t 170° (24 mm.), and gave,1410 GILBODY, PERKIN, AND YATES : on analysis, numbers which show that it consisted of piire ethyl m-naethoxyphenoxyacetate, OMe* C,H,*O* CH,*CO,Et.0.1545 gave 0,3545 CO, and 0.0946 H,O. Cl1HI4O4 requires C = 62.8 ; H = 6.7 per cent. Hydrolysis.-When this ester (21 grams) was mixed with a filtered solution of 10 grams of potassium hydroxide in methyl alcohol, a good deal of heat was deveIoped, and in a short time the mass became semi- solid, owing to the separation of a white, crystalline potassium salt,. This was collected on the pump, washed well with methyl alcohol, and recrystallised from this solvent; it was thus obtained i n colourless needles, which are very sparingly soluble in cold methyl alcohol, but readily soluble in water. The aqueous solution of this salt gave, on acidifying, an oily precipitate which rapidly solidified, and by carefully crystallising from water, colourless needles were obtained, which were analysed, with the following results : (2-62.6 ; H=6% OW1840 gave 0.3998 CO, and 0.0932 H,O.C = 59.3 ; H = 5.6. UgHl,O, requires C = 59.3 ; H = 5.5 per cent. The m-methoxyphenoxyacetic acid thus obtained softened at 116' and melted at 118-119'; it is identical with the acid obtained from the 2-carboxy-5-methoxyphenoxyacetic acid from brazilin (see above), since an intimate mixture of the two preparations melted at the same temperature as the constituents. Brccxilinic Acid, ClgHl,Og, and Brasilic Acid, Cl,Hl2O,. When the chloroform extract of the acidified oxidation product of trimethylbrszilin (see p. 1405) is left for some days, it usually solidifies, but it was found impossible to obtain any crystalline products directly from it by treatment with organic solvents on account of the consider- able quantity of resinous matter which it contains; it may, however, be purified in the following way.The resinous mass obtained from each 10 grams of trimethylbrazilin is boiled with half a litre of water, filtered frQm a varying quantity of insoluble tarry matter, the filtrate evaporated to about 100 c.c., and allowed to stand for 2 or 3 days. The crystais which have then separated are collected on the pump, washed with water, and dissolved in a little glacial acetic acid, from which solution the brazilinic acid slowly separates in hard, colourless crystals. After recrystallisation, this acid melts at 208O and gives numbers on analysis agreeing with those required for the formula ClgHl,Og. It therefore contains the same number of carbon atoms as trimethylbrazilin.BRAZILIN AND HbMATOXYLIN. PART I. 1411 0.1722 gave 0.3698 CO, and 0.0715 H,O. C=58*6 ; H=4*6. 0.1928 ,, 0*4112 CO, ,, 0.0789 H,O. C =58.2 ; H=4*6. C,gH,,09 requires C = 58-5 ; H = 4.6 per cent. The aqueous filtrate from the crude brazilinic acid is made slightly alkaline with sodium carbonate and evaporated to a small bulk, when, on standing, crystals of the sparingly soluble sodium salt of brazilic acid gradually separate. This salt is collected on the pump and recrystallised twice from water, from which it separates in satiny plates. It is then dissolved in water and acidified and the voluminous, needle-shaped crystals of the free acid are collected on the pump and purified by crystallisation from water, Brazilic acid melts at 129' and is readily soluble in hot, but only sparingly so in cold, water. On analysis : 0.1337 gave 0*2788 CO, and 0.0640 H,O. C = 56.9 ; H = 5.3. 0.1431 ,, 0'3003 GO, ,, 0.0623 H,O. C=57.2 ; H=4% C12H:1206 requires C = 57.2 ; H = 4-8 per cent. The amount of brazilinic acid obtained by the oxidation of trimethyl- brazilin is considerable, 1 kilo. yielding about 50 grams of the pure acid. On the other hand, brazilic acid is only produced in very small quantities, the average yield being about 7 grams from this quantity of trimethylbrazilin. Both these acids are, at the present time, being subjected to a careful examination, and i t is hoped that the results which are being obtained will throw much further light on the ques- tion of the constitution of brazilin. We wish a t this stage to express our thanks to the Government Grant Committee of the Royal Society for the repeated grants which they have given us in aid of this work. THE OWENS COLLEGE, M BNUHESTER.

ISSN:0368-1645    

DOI:10.1039/CT9017901396

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

INDEX OF AUTHORS' NAMES. T RA N SAG T I 0 N S. 190 1. (Marked T.); and to Proceedings of the Session 1900-1901; Nos. 227 to 240, Nov., 1900--June, 1901 (marked l'.). COMPILED BY MARGARET D. DOUGAL. A. Abell, Robert Duncombe, the condensa- tion of phenyl ethyl ketone and tienz- aldehyde, T., 928; P., 1901, 128. Ackroyd, Willkwn, researches on moor- land waters. Part 11. On the origin of the combined chlorine, T., 673; P., 1901, 87. Allison, J. R. See Arthur Gcorge Perkin. Arbuckle, William. See Alexander Scott. Armstrong, Henry' Edzuard, and T. M Lowry, stereoisorneric a- and a'-sulpho- iiic derivatives of camphor, P., 1901, 182. Armstrong, Hemy Edwcwil, and Leomrd Philip Wilson, 1 : 2 : 4-rn-xylidiiie-6- sulphonic acid, P., 1900, 229. Aston, Bemard Cracroft. See Thoinas Hill Easterfield.Aston, Francis 1V. See Percy Fiirtcdmy Frankland. Aston, Henry. See Percy Rcttwlay Frankland. Atkinson, Edm?6nrl, obituary noticc: of, T., 872, 888. B. Barbour, TVilliami. See Tholitas Purdie. Bau~or, Barold W. See Siegfried Ruhemann. Beilby, George Thomas, ind George Gwalcl Henderson, the action of ammonia on metals at high temperatures, T., 1245 ; Bell, Chichester A., a calibrating mercury pipette, P., 1901, 179. Bevan, E'dwartl JOJLIL. See Charles Freilcrick Cross. LXXIX. P., 1001, 190. Bone, William Arthur,and David Smiles Jerdan, the direct union of carbon and hydrogen. Part II., T., 1042 ; P., 1901, 162. -- the decomposition of hydro- carbons at high temperatures : pre- liminary note, p., 1901, 164. Bose, R. Chimi Lal, on the chemistry of 2l'eriion odoram, P., 1901, 92. Boyd, D. R., action of the chlorides of phosphorus on aromatic ethers of glycerol. Diaryloxyisopropylphos- phorous acids, T., 1221 ; P., 1901,188. Branner, Bohibslav, on the atomic weight of praseodymium, P., 1901, 65. - on praseodymium tetroxide and peroxide, P., 1901, 66. - note on neodymium, P., 1901, 66. - chemistry of thorium, P., 1901, 67. Brauner, BOJLUS~~V, and F. PavliEek, the atoniic weight of lanthanum and on the error of the " sulphate method ') for the determination of the equivalent of the rare earths, P., 1901, 63. Brown, Hcwold. See 1Vywdhanb Rowlccntl Dunstan. Burgess, Chnrles Rutchews, and David Leonard Chapman, non-existence of the so-called suboxide of phosphorus. Part 11. Burgess, JIubert Edward, two new substances in lemon oil, P., 1901, 171.T., 1235 ; P., 1901, 189. C. Carter, William, and William Trevor Lawrence, derivatives of ethyl a- methyl-B-phen ylcyanoglutarate, P., 1900, 178. Carter, William See also Robert Hmuson Bickard. 5 E1414 INDEX OF AUTHORS. Caven, EobeYt ilIiwt in, organic derivatives of phosphoryl chloride and the space configuration of the valencies of phos- phorus, P., 1901, 26. Chapman, Alfred Chnstoiz, santnlenic acid, T., 134 ; P., 1900, 204. Chapman, David Leonnrcl, See C ' h rles Ezbtchens Burgess. Chapman, Edgar N u ~ s h . See A~thzi/. Lapworth. Chat t awa y, Frederick Danicl, and Kenitedy Joseph Previte Orton, tlie preparation of acetylchloroamino- benzene and some related compounds, T., 274 ; P., 1900, 231. -- the action of acetylchloro- a i d acetylbromo-aminobenzenes on amines and phenylhydrazine, T., 461 ; P., 1901, 38.-- the preparation of o-chloroanil- ine, T., 469; P., 1901, 39. -- the symmetrical chlorodi- bromo- and dichlorobromo-aniline~ and chloro- and bromo-amino-deriva- tives of chlorobromoacetanilides, T., 816 ; P., 1901, 124. -- the replacement of bromine by chlorine in anilines, T., 822 ; P., 1901, 126. Clarke, G. See Frederic Stanley Kip ping. Cohen, Jzclizcs Berend, and Henry Drys- dale Dakin, the aluminium-mercury couple. Part 111. Chlorination of aromatic hydrocarbons in presence of the couple. The constitution of the dichlorotoluenes,T.,llll ; P., 1901,91. Cohen, Julius Berend, and C. A!. White- ley, experiments on tlie production of optically active compounds from in- active substances, T., 1305 ; P., 1900, 212.Collie, John Norman, on the decom- position of carbon dioxide when sub- mitted to electric discharge a t low pressures, T., 1063 ; P., 1901, 168. Collie, John iVorman. See also W. Crossley, Artlrw lVilliattz, preparation and propertics of 2:6-diketo-4-iso- propylhexamethylene (2:6-dihydroxy - 4 - isopropyldihydroresorcinol), P., 1901, l i 2 . D. Dakin, HenYy DrysduZe. Sce Jidius Bevend Cohen. Dawson, Harry Jldfortlz, en the nature of polyiodides and their dissociation in aqueous solution, T., 238 ; P., 1900, 215. Dawson, .Harry Jle@orth, and Jokn XcCrae, metal-ammonium compounds in aqueous solution. Part 11. The absorptive powers of dilute solutions of salts of the alkali metals, T., 493 ; P., 1901, 5. -- metal-ammonia compounds in aqueous solution. Part I [I.Solutions of salts of the alkaline earth metals, -- me td-ammonia coinpounds in aqueous solution. Part I V . The in- fluence of temperature on the dissocia- tion of copper-ammonia sulphate, T., 1072 ; P., 1901, 178. Dickinson, Cyril. See Thonzns S. Patter- son. Divers, Edward, and Tamemasa Haga, nitrilosulphates, T., 1093 ; P., 1901, 164. Divers, Edward, and Kasataka Ogawa, ammonium and other imidosulphites, T., 1099; P., 1900, 113 ;. 1901, t63. Dixon, A ~ L ~ ~ C S ~ Z C S Edward, interactlon of urethanes and primary benzeuoid amines, T., 102 ; l',, 1900, 207. - a form of tautomerism occurring amongst the thiocyanates of electro- negativo radicles, T., 541 ; P., 1901,50. - halogen-substituted thiosinamines, T., 553 ; P., 1901, 49.Dobbie. Jcmes Joknstone, AZexancle~ 'r., 1069; P., 1901, 177. Lauder, and P?~olios G. Paliatseas, the alkaloids of Corydcdis cava : conversion of corybulbine into corydaline, T., 87 ; Gamed. Conroy, Sir John, obituary notice of, , --,. - * ^ ^ ^ --- 'I,, 88Y. I Y., lVU0, 205. Corstorphine, Ilobert Henry. See George Gerald Henderson. Crompton, Holland, note on the latent heats of evaporation of liquids, P., 1001, 61. Cross, ChrZes Frederick, and Edxard John Bevan, the ketonic constitution of cellulose, T., 366; P., 1901, 22; discussion, P., 23. Dobbie, James Joknstone. See also Walter Noel Hartley. Dootson, Frederick William See WiEZiam James Sell. Doran, Robert EZZiott, the action of lead thiocyanate on the chlorocarbonates. Part JI. Carboxymethyl- and carboxy- amyl-thiocarbimides and their deriva- tives, T., 906 ; P., 1901, 130."*""-".J, _A. "I"_. , I """"W ,.., Yl." 4..""*."V -L"c"",", cm l Y I l u I L l " Y " 1 v . - -- tion of ethyl sodiomethylmalonate and I y " ~ i ~ ~ e ~ ~ ' s t,cAst for arsenic, T., 715 ; P., mesityl oxide, 'I?., 135 ; P., 1900, 90. 1901, 92.INDEX O F AUTHORS. 1415 Brown, tile alkaloid of iyyOSCgi6iWLS muticus and of Dnticra Stramlnium grown in Egypt, T., 71 ; P., 1900, 207. Dingtan, Wyndhanz Rozclnizd, and Ernrst Goulding, the action of alkyl haloids on aldoximes and ketoximes. Pert 11. Alkylated oximes and iso-oximes, and the constitution of aliphatic osiines, T., 628 ; P., 1901, 84. -- the supposed existencc of two isomeric triethyloxamines, T., 641 ; P., 1901, 85. Dyer, Charles Sta)zZe!y.See TPiZlirtiiz Arthzw Harrison Naylor. E. Easterfield, Tho iilcbs Hi17, and Bt~mcwrl Cmcroft Aston, tutu. Part I. Tutin and coriamyrtin, T., 120 ; P., 1900, 211. Ellis, Tizoinas Floiue~, obituary notice of, T., 872. Eyre, John Targas. See Ruphncl Mel- dola. Eyre, Jillimz. See George Young. F. Farmer, Robert Crosbie, a new method for the determination of hydrolytic dissociation, T., 863 ; P., 1901, 129. Farmer, Robed Crosbie. See also Perry FamcEccy Frankland. Fenton, IIenry John Horstmun, note 011 the sugars of cellulose, P., 1901, 166. Fenton, Hewy John Eorstman, and (Afiss) Mildyed Gostling, the action of hydro- gen bromide on carbohydrates, T., 361 ; P., 1901, 22. _-- - derivatives of methylfurfural, T., SO7 ; P., 1901, l i 9 ; discussion, P., 119.Fenton, Henry John Horstmm, a d H~6mphrcy Owe?& Jones, relationships of oxalacetic acid, T., 91 ; P,, 1900, 205. -- note on a method for compar- ing the affinity values of acids, P., 1901, 24 ; discussion, P., 26. Forster, Alartin OnsZow, infracamphol- enic acid, an isomeride of campholytic and isolauronolic acids, T., 108 ; P., 1900, 211. - studies in the carnphane series. l'art 11. Nitrocamphenc, aminocam- pliciie, and hydroxycainl~liene, 'J',, 644 ; P., 1901, 85. of 6ydroxylamine on the anhydrides of bromonitrocalilphalle, T., 653 ; P., 1901, 88. - studies in the cainphane series. Part IV. The isonicrism of a-benzoyl- caniphor, T., 987 ; P., 1901, 167. Forster, Nnrtiiz Oijsloiu, and TYiZliam Robertson, preparation and properties of 2:6-dil~romo-4-nitrosophenol, T., 686 ; P., 1901, 116.-- stutlies in the camp1iane:series. Part V. Halogen derivatives of 11- cymene from substituted nitrocam- phanes, T., 1003 ; P., 1901, 169. Fowler, Gilbert John, iron nitride, T., 285 ; P., 1900, 209. Fowler, Gilbert J O ~ I L , and PJi ilip Joseph Hartog, the heat of formation and constitution of iron nitride. T., 299 : , , P., 1900, 210. Fox. JoIm Jacob. See John TI~eoclore Hewitt. Frankland, Percy Famday, and Francis W. Aston, influence of a heterocyclic group on rotatory power ; the ethyl and methyl esters of dipyromucyltartaric acid, T., 511 ; P., 1901, 41. Frankland, Percy Farnday, and Eobert Cyosbie Farmer, liquid nitrogen per- oxide as a solvent, T., 1356 ; P., 1901, 201. Frankland, Percy Paraday, Frederick MaZcoZm Wharton, and Hewy Aston, the amide, anilidc, and 0- and p-toln- idides of glyceric acid, T., 266 ; P., 1901, 6.G. Garrett, F~*eclericlc C'ILcct.le.9, and JoJm Amnstrong Smythe, the bases contained in Scottish shale oil, P., 1900, 190. Garsed, TV., and John Normnn Collie, on the estimation of cocaine and on cocaine hydriodide pcriodidc, T., 675 ; P., 1901, 89. Gilbody, Alexander William, and Charles H. G. Sprankling, the in- fluence of the methyl group on ring formation, P., 1900, 224. Gilbody, Alexander TTiUium, JVi'illiam Henry Perkin, jzm., and J. Pates, brazilin and hzematoxylin, T., 1396 ; P., 1899, 27, 75, 241 ; 1900, 105. Goodwin, Williccm. See A @ed Senier. Gordan, Paul, and Leonhnrd Limpach, some relations between physical con- stants and constitntion in benzenoill amines.Part II., T., 1080 ; P., 1901, 154. 5 E 21416 INDEX OF AU't'HOKS. Gostling, (Jliss) Afilclred. See Hcnry John HorstrnasL Fenton. Goulding, Erizcst. See Wpdlznnt Rowlnnd Dunstan. Gray, Thonzas, note on acetonylacetone, T., 681 ; P., 1901, 89. - condensation of acetonylacetone with hydrazine hydrate, T., 682 ; P., 1901, 90. Guye, Philippe A., optical activity of certain ethers and esters, 'I?., 475 ; P., 1901, 48. H. Haga , T@?netnasa. See Edzuard Divers. Hall, Earold. See Fredcric Xtadey Kipping. Harden, Arthur, the chemical action of BacilZus eoli co??zrnunis and similar organisms 011 carbohydrates and allied conipoiinds, T., 610 ; P., 1901, 57 ; discussion, P. , 58. Harden, Arthur, and J. Okell, note on the action of nitrous acid on B-nitroso- a-naphthylamine, P., 1900, 229. Harden, Arthur, and Xydney Rowland, autofermentation and liquefaction of pressed yeast, T., 1227 ; P., 1901, 189. Kartley, Walter Noel, James Jolznstonc Dobbie, and AEexander Lauder, the absorption spectra of cyanogen com- pounds, T., 848 ; P., 1901, 125. Hartley, ?Valter Noel, and Hugh Ramage, a simplified method for tlie spectrographic analysis of minerals, T., 61 ; P., 1900, 191. Bartog, Phizip J o M ~ ~ L . See Gilbert J o l ~ Fowler. Harvey, Alfred TViZlianz. See TVillum Jackson Pope. Hatfield, H. S. See William Ramsay. Xenderson, Gcorgc Gcrald, and liobcrt Henry Corstorphine, condensation of b e n d with dibenzyl ketone, T., 1256 ; Henderson, Gyeotyc Gernld. See also George Thomas Beilby. Henry, Thomas A?Ldersou, the constitu- ents of the sandarac resins.T.. 1144 : P., 1901) 190. I , P., 1901, 187. Hewitt, JoJm Theodore, and Joh,ih Jacob Fox, 'the nitration of beiizeneazosali- cylic acid, T., 49 ; P., 1900, 189. Hewitt, John Theodore, and James .Henry Lindfield, the nitration of the three tolueneazophenols, T., 155 ; P., 1900, 222 ; discussion, P., 222. Hewitt, Jolm Theodore, and Henry Ablett Phillips, the broinination of o-oxyazo- componnds and its bearing on their cwustitutioii, T., 160 ; P., 1900, 223. Hewitt, John T?u?odore, and Johi N. Tervet, action of bromine on the three tolueneazophcnols, T., 1090 ; P., 1901, 172. Hill, Arthis?' Croft, a nicthod of isolating maltose when mixed with glucose, P., 1901, 45. - taka-diastase and reversed ferment action, P., 1901, 184. Hird, James AIorton.See Frank Geo. Pope. Holmes, John. See T11,omas Edtoiwd Thorpe. Holroyd, Geoqe W. F., the electrolytic reduction of nitrourea, T., 1326 ; P., 1901, 197. Hunter, Albert E. See Frcderic Stanley Kip ping. Hurtley, li~illinm Holdszuorth, tlie chlorodibromo- ant1 dichlorobronio- benzenes, T., 1293 ; P., 1901, 191. I. Innes, WilCimitz Eoss, note on tlie use of pyridine for molecular weight deter- minations by the ebullioscopic method, T., 261 ; P., 1900, 223. Irvine, Jai~zcs C., preparation of o-di- niethoxybenzoin, and a new method of preparing salicylaldeliyde methyl ether, T., 668 ; P., 1901, 88. Irvine, Jattws C. See also Tho?nns Purdie. J. Japp, 3rmci.s Ilobert, and W. Maitland, formation of carbazoles : preliminary note, P., 1001, 176. Japp, Francis Robert, and Aitclrew N.Meldrum, honiologues of anliydrace- tonebenzil, T., 1024; P., 1901, 174. Japp, .Francis aobert, and Artl~i~r 6'. Michie, reduction of ay-dibenzoyl- propane and dibenzoyldiphenylbutadi- ene, T., 1010 ; P., 1901, 173. Jerdan, Dwkl Xtnilcs. See 7YiZlicm Jollyman, Walte,. IZenq/. See lVdter Charles Cross Pakes. Jones, Humphrey Owen. See Hetiry JoIL~ Horstman Fenton. Jowett, Hooper Albert Dickiwon, the constitution of pilocarpine. Parts 11. and 111.) T., 580, 1331 ; P., 1901, 56, 198. - a new synthesis of a-ethyltri- carballylic acid, T., 1346 ; l'., 1901, 199. A Ttht6T Bone.INDEX OF AUTHORS. 1417 K. Kipping, Frcderic Stnnlcy, isomeric hydrindamine camphor-x-sulphonates ; racemisation of a-bromocamphor, T., 370 ; P., 1901, 32. - experiments on the production of optically active compounds from in- active substances, P., 1900, 226.Kipping, Frcderic Xtanley, and (7. Clarke, a-amino-8-methylhydrindene, Kipping, Frecleric Stnttley, and Harold Hall, isomeric salts containing quin- quevalent nitrogen. Part VII. Benzyl- hydrindamiiie 1,romocampliorsulphon- ates, T., 430 ; P., 1901, 37. -__. isomeric hydrindaiiiine man- delates and phenylchloroacethydrind- amides, T., 442; Y., 1901, 36. Kip ping, Frederic Stadey, and Albert E. Hunter, pheno-a-ketoheptamethyl- ene and its derivatives, T., 602 ; P., 1901, 68. Kipping, Freclei*ic Stanley, and Lorcico Lyddo?t Lloyd, organic derivatives of silicon ; triphenylsilicol and alkyloxy- silicon chlorides, T., 449 ; P., 1901, 32. P., 1901, 1s1. L. Lander, Geurge Dmcc, slkylation of acylarylamiiies, T., 690 ; P., 1901, 59.- preparation of alipliatic iniino- ethers from amides, T., 701 ; P., 1901,6 1. -- action of dry silver oxide and ethyl iodide on benzoylacetic ester, deoxy- benzoin, and benzyl cyanide, P., 1901, 59. Lapworth, Arthw, the form of change in organic compo~nds a d the function of the a-meta-orientating groups, T., 1265; P., 1900, lOS, 132; 1901, 2, 93, 95. - note 011 isomeric change and ineta- sulxditution in benzenoid amines, P., 1901, 2. Lapworth, Aythur, and Edgccr J1ars7t Chapman, aa-hydroxycamphorcarb- oxylic acid, T., 377 ; P., 1901, 28. Lapworth, Arthur, and Wcclter Henry Lenton, the constitution of caniphanic acid and of bromocamphoric anhydr- ide, T., 1284 ; P., 1901, 37. -- the constitution of the acids obtainrd from a-dibromocamphor, P., 1901, 148. I,arter, A .T., displacement of alkyls from phenols by nitration. 1. Thyin- 01, P., 1901, 183. Lauder, Alemnde~. See James JohnstoPte Dobbie, ancl Walter Noel Hartley. Lawes, Sir John Bemet, obituary notice Lawrence, William Tyevor, and Willic~nz Henry Perkin, jun., formation of aromatic compounds from ethyl gluta- conate and its derivatives : the reduc- tion of trimesic acid and the conversion of tetrahydrotrimesic acid into tetra- hydroisophthalic acid, P., 1901, 47. Lawrence, WiZlimn Trevor. See also Williana Carter. Lee, Theophilus Henry, note on tecomin, a colouring matter derived from the lieart-wood of Bignonia Tecortm, T. , 284 ; P., 1901, 4. Lees, Frederick H., and TVilliain Hewy Perkin, juu., the action of aluminium chloride nn camphoric anhydride, T., 332 ; P., 1898,111 ; 1899,23 ; 1900,lS.Lees, Freclerick H. See also Samuel Barnett Schryver. Lenton, Wc6lter Heizry. See Artlmt. Lapworth. Le Sueur, IIcwg EortdeZ, the products of tlie action of fused potassium hydroxidc on dihydroxystearic acid, T., 1313 ; l'., 1900, 91. Limpach, L C O I ~ L C L ~ ~ . See Prbicl Gor- dan. Lindfield, Jnmcs Henry. See Joht Tlaco- rlore Hewitt. Lloyd, Lorenzo Lyclclon. See Frcderie Staulcy Kipping. Lowry, 5". M. See Hcwy Eclzuard Armstrong. Lumsden, Johib ,Y. of, T., 873, 890. See Jnines Walker. M. Macadam, Stcveiason, obituary notice of, T., 897. McCrae, Johu, ethyl sec. octyl tartrate and its dibenzoyl and diacetyl derivatives, T., 1103 ; P., 1901, 186. McCrae, Jolm. See also 1.arry Mcdforth Dawson.PcKenzie, A Zcxrmdcr, the esterification of 3-nitrophthalic acid, T., 1135 ; P., Mackenzie, Johia Eclwin, tlie action of' sodium methoxide and its homolognes on benzophenone chloride ancl beiizal chloride, T., 1204 ; P., 1901, 150. Madan, Hemy Geol-ge, the colloid form of piperine, with special reference to its refractive and dispersive powers, Maitland, W. See Fruncis Robert Japp. Markownikoff, Wladintir B., congratu- latory address to, and his reply, l'., 1901, 186. T., 922 ; r., 1901, 127. 1901, 1, 83.1418 INDEX OF AU‘L’IIORX. Martin, Um-les Jcmcs, and c)1viLc Masson, the influence of cane sugar 011 the conductivities of solutions of potassium chloride, hydrogen chloride, and Dotassium hydroxide. with evidencc of s i l t formatioii iii the‘ last case, T., 707 ; P., 1901, 91.Martin, G. , on a theory of clieniical com- bination, P., 1901, 169. Masson, [David] Orme. See CJmrlcs JknLes Martin. Matthews, Francis Edward, 2 : 3 ; 5-tri- chlorobenzoic acid, T., 43 ; P., 1900, 187. Meldola, Raplzael, aiid J o h Va~yns Eyre, additional notes on dinitro-o- anisidine : a chemical reaction in which one of the products continues the same reaction, T., 1076 ; P., 1901, 131, 185. Meldola, BapJ~aeZ, and Pmlc?.iek Wil- Zinii~ Streatfeild, note on Gallinek’s amiiiometliylnaphiniin~zole, P., 1900, 183. Meldola, XapJml, and EZkaii Wechsler, the nitration of acetamino-o-phenyl acetate (diacetyl-o-aniinophenol) : a correction, P., 1900, 180. Meldrum, AqLdrcw iV. See Francis Robert Japp. Mellor, J. W., some a-alkyl sulJstitution products of glutaric, adipic and pimelic acids, T., 126; P., 1900, 215.- on the union of hydrogen and chlorine. Parts I. to III., T., 216 ; Michie, Artln6r C. See Ft*aw:is Xobert Miers, IIm~ry Alexander, Rnmnielsberg memorial lecture, T., 1 ; P., 1900, 219. Mills, TV. Xloan. Blair, James, 0- and p-cyanohydroxy- derivatives of pyridine, Y., 1901, 69. Moody, Iierbert R. See Xainiicl Auch- wwty Tucker. Morris, George HwrL‘s, the combined action of diastase and yeast on starch- granules, T., 1085 ; P., 1901, 178. P., 1900, 221. JaPP- Bee Hicgh Ryan. N. Naylor, ?vLlliwth A t*tlm,t* Jrrwt’iso?t, a i d C1~wZcs ASta~i7cy Dyer, orosylin, T., 954 ; P., 1901, 118. Neville, A12r.1~ See Robct*l IUwsoIi Pickard. Newth, G. S., a laboratory nietliod for the preparation of cthylene, T., 915 ; P., 1901, 147.0. Oates, TVillintiL €Ici~q. See Gcorgc Ogawa, Masataka. See Edward Divers. Okell, J. See Arthur Harden. Orton, Kei~ncdy Joseph Previte benzoyl- ation of fatty acids in the presence of amnionin ; formation of amides, ‘l‘., 1351 ; P., 1901, 200. Orton, Kennady JOSC~JL Prcvite. See also Fredcrick Daniel Chattawav. Young. O’Sullivan, Cornczizu, gum iragncantll, T., 1164 ; P., 1901, 156. P. Pakes, 7VaZtcr C’JLarZcs Cross, and CYaZtw Henry Jollyman, the collection and examination of the gases produced by Bacteria from certain media, T., 322 ; l’., 1900, 189. -- the bacterial decomposition of formic acid into carbon dioxide a i d hydrogen, T., 356 ; l’., 1901, 29. -- the bacterial oxidation of forinates by nitrates, T., 459 ; l’., Paliatseas, P7~otios G.See Jimcs Job- stone Dobbie. Patterson, Thomas X., tlic influence of solvents on the rotation of optically active compounds. Part I. Influence of water, methyl alcohol, ethyl alcohol, qc-propyl alcohol, and glycerol on the rotatiop of ethyl tartrate, T., 167 ; P., 1900, 176. - the influence of solvents on the rotation of optically active compounds. Part 11. Influence of isobutyl alcohol and of sec.octy1 alcohol (methylhexyl- carbinol) on ethyl tartrate, T., 477 ; l’., 1901, 40. Patterson, TJwnzas X., and Cyril Dickin- son, the preparation of esters from other esters of the saiiie acid, T., 280; Pavikiek, F. Peachey, Xtmdey John. See WilZicoiz. Jnekscnt Pope. Perkin, Art?r iir Guorgc, robinin, viola- quc~citrin, aiid oeyritriii, 1’., 1901, 87. Perkin, At,t7~iii* Gevry(,, and J. 1:. Allison, rhamnazin a i d rliamnetin, P., 1900, 151. Perkin, Aifhw Gycoiyc, and E. J. Wilkinson, the colouring matter of the flowers of UcQhiniim Coizsoliiln, 1’. , 1901, 39. P 1901, 4. See Boh iislav Brauner. 1900, 1s3.INDEX OF AUTHORS. 141 9 Perkin, William Henry, jun. , tetra- niethylenecarbinol, T., 329 ; P., 1901, 33. - synthesis of isocamphoronic acid, P., 1900, 214. Perkin, William Henry, jm., and Jocelyn Field Thorpe, [and, in part, C. Walker], the synthetical formation of bridged rings. Part I. Some cleriva- tives of dicyclopentane, T., 729 ; P., 1900,149 ; 1901, 110. Perkin, William Hewy, jziu., and J. Yates, the action of aluminiuin chloride on camphoric anhydride, T., 1373 ; P., 1898, 111 ; 1899, 23 ; 1900, 18.See also Alcxandcr William Gilbody, 1V;lliccm Trevor Lawrence, and Fmlcrick H. Lees. Perman, Edgar Philip, vapour prassure of aqueous ammonia solution. Part I., T., 718 ; P. 1901, 46. - influence of sodium sulphatc on the vnpour pressure of aqueous ammonia solution, T., 725 ; P., 1901, 47. Phillips, Hewry Ablctt. See JoJm Tlzeodow Hewitt. Pickard, Eobert Hotuson, and William Carter, formation of aniides from alde- hydes, T;, 520; P., 1901, 45. -- nydroxyoxamiiles, T., 841 ; P., 1901, 123. Pickard, Kobcrt Howson, and A llan Neville, note on pyromucylhyclrosainic acid, T., 847 ; P., 1901, 127. Pope, Prank Geo., and Janzw Illwton Hird, derivatives of 3-nitrotolyl-4- liydrazine, T., 1141 ; P., 1901, 186. Pope, William Jackson, and A ?frcd IViZliam Harvey, the inversion of the optically active ac- tetra- hydro-& iinphthylamiiies prepared by the aid of d- and l-bromocamphorsulphonic acids, T., 74 ; P., 1900, 206.-- optically active nitrogen com- poiincls and their bearing on the valency of nitrogen ; d- and-l-a-benzylphenyl- allylmethylainmoniuni salts, T. , 828 ; P., 1901, 120 ; discussion, P., 121. Pope, William Jackson, and Xtcoi leg John Peachey, asymmetric nptically active sulphur compounds ; d-methyl- ethylthetine platinichloride, P., 1900, 163. Price, Thomas Slntcr, the reaction between ethyl alcohol and hydrochloric acid, T., 303 ; P., 1900, 185. Purdie, Thouzus, and William Barbour, the influence of solvents on the rotatory powers of ethereal dimethoxysuccinstes and tartrates, T., 971 ; P., 1901, 158.Perkin, William HenrU, j u n . Purdie, Thontas, and James C. Irvine, optically active dimethoxysuccinic acid arid its derivatives, T., 957 ; P., 1901, 157. R. Ramage, Hugh. See Walter Noel Hartley. Rammelsberg, Karl Fiiedrich, memorial lecture on (Miers), T., 1; P., 1900, 219. Ramsay, William, note on the supposed formation of an oxide of hydrogen higher than the dioxide, T., 1324 ; P., 1901, 197. Rzmsay, Williccm, and H. S. Hatfield, preliminary note on hydrides of boron, P., 1901, 152. Ramsay, Williaiic, and George Rudorf, the action of heat on ethylsulphuric acid, P., 1900, 177. ROy, Prafidla Chandra, a new series of dimercuriainmonium salts. Part I. , P., 1901, 96. Reynolds, Richard, obituary notice of, T., 873. Richardson, Arthur, a kerosene oil blow- pipe, P., 1901, 151.Robertson, TYilliam. See Martin Ons- low Forster. Rowland, Sydxey. See drtht6r Harden. Rudorf, Georgc. See William Ramsay. Ruhemann, Bieg fried, condensation of phenols with esters of the acetylene series. Part V. Honiologues of benzo- 7-pyrone, T., 918 ; P., 1901, 155. Ruhemann, Siegfried, and Harold W. Bansor, condeiisatioii of phenols with esters of the acetylene series. Part I V . Benzo-y-pyrone and its homo- logues, T., 470 ; P., 1901, 40. Ruhemann, Siegfried, and Eruest Wragg, coiidensation of phenols with esters of tlie acetylene series. Part VI., T., 1185 ; P., 1901, 167. Ryan, Htbgh, and 1F. Xloa~t Mills, preparation of synthetical glucosides, 11.) T., 704 ; P., 1901, 90. S. Schryver, SantzieE Bcwnett, and Frederick H. Lees, researches on morphine.Part 11, T., 563 ; Y., 1901, 51. Scott, Alexandcr, ammonium bromide and the atomic weight of nitrogen, T., 147 ; P., 1900, 204. Scott, Alcxaitcle?., aiid William Arbackle, the preparation of iodic acid, T.: 302 ; r ) 1901, 2.1420 INDEX OF AUTHORS. Sell, William James, and Fwdcrick William Dootson, the chlorine deriva- tives of pyridine. Part VIJ. Some condensation products, T., 899 ; P. , 1901, 131. Senier, Ayred, a lecture table experiment for the preparation of nitric oxide, P., 1900, 227. Senier, AIfred, and lV,illiniia Goodwin, the action of ethylene dibroniide on xylidine and 4-cnmidine, T., 254 ; P., 1900, 228. -- action of pheiiylcarbimide on diphenyl-, dialphyl-, and dinaphthyl- diamines, T., 258 ; P., 1900, 228. Shaw, Saville, obituary notice of, T., 875.Simmonds, Clmrlcs. See Thoiitas Ed mud Thorpe. h y t h e , John Armntrong. See Fredcric?; Charles Garrett. Sodeau, Willicsii~ Horncr, the deconiposi- tion of chlnrates. Part 111. Calcinm chlorate anti silver chlorate, T., 247 ; P., 1900, 209. - the decomposition of chloratcs. Part IV. The supposed mechanical facilitation of the decomposition of potassium chlorate, T., 939 ; P., 1901, 149. Sprankling, CJLCWZ~S H. G. See Alex- m d c r lViZZia?it Gilbody. Steele, Bcrtrnnz D., a new method for the mensuremeat of ionic velocities in aqueous solutioii, T., 414; P., 1901, 5. Stern, Arthur Landnzscr, the nutrition of veast. Part 111.. T.. 943 : I?., , . I , 19Oi, 126. Streatfeild, Frdorick William. Sec Kaphael &eldola. Sudborough, John Joseph,, additive com- pounds of a- and 8-naphthylamine with trinitro-derivatives of benzene, T., 522; P., 1901, 44.- acetylation of arylamines, T., 533 ; P., 1901, 45. - iiornenclature of the acid esters of unsymmetrical dicarboxylic acids, P., 1901, 43. - note on diphenyldinitroethylcnc, P., 1901, 68. T. Tervet, John N. See JOIL~L Theodore Thorpe, Jocelyn FieZd. See William Thorpe, Thomas Edward, presidential Hewitt. Henry Perkin, jun. address, T., 871 ; P., 1901, 70. Thor pe , Thorn a s Edwa i d , a i d Joh i L Holmes, the occurrence of paraffins in the leaf of tobacco, T., 982 ; P., 1901, 170. Thorpe, Thomas Edward, and Chcwlos Simmonds, lead silicates in relation to pottery manufacture, T., 791 ; P., 1901, 113 ; discussion, P., 114. Titherley, LArthw Walsh, the prepar- ation of substituted amides from the correspoiiding sodamides, T., 391 ; P., - a new method of pre1)aring diacet- amide, T., 411 ; P., 1901, 31. - note on two molecular compounds of acetamidc, T., 413; P., 1901, 31. Tucker, S a m d Az~hwvi@j, aiid Herbert 12. Moody, thc production of some new metallic borides, P., 1901, 129. 1901, 29. W. Walker, C. See Williim lIe1~1.y Perkin, jwn. Walker, JCL~IZCS, and John S. Lumsden, the hydrobroinides of unciecylenic acid, T., 1191 ; P., 1901, 188. -- n-decanedicarbosylic acid, T., 1197 ; P., 1001, 188. Wechsler, E'lI;.ait. See Rnphncl IvIel- dola. Wharton, Ft.eclc~ick Alalcolm. See Percy Farcsdny Frankland. Whiteley, C. E. See Jiclizts Bcrend Cohen. Wilkinson, E. J. See Arthur Georgc Perkin. Wilson, Leonard Plhilip. See Bcnry Edwayd Armstrong. Wragg, Bnzcst. See Sie&ried Ruhe- mann. Wynne, ZViZlinsit Palmer, the chlorina- tion of toluene, P., 1901, 116. Y. Yates, J. Sec TVilliism H e w y Perkin, j m , and Alecanclcr Wi'lliaw~ Gilbody. Young, Gcorge, and William Eyre, oxid- ation of benzalthiosemicarbazone, T., 54 ; P., 1900, 188. Young, Gcorp, and IVillinm l i e w y Oates, contribution to the chemistry of the triazolcs ; 1-methyl-5-liydrosytri- nzoles, T., 659 ; P., 1901, 86 ; discus- sion, P., 87.

ISSN:0368-1645    

DOI:10.1039/CT9017901413

出版商:RSC    

年代:1901

数据来源: RSC