摘要:

FORMATIOX OF MONOMETHYLANILINE FROM DIMETHYLANILINE. 163 X.-Formation of Monomethylaniline from Dimethylaniline. By JULIUS B. COHEN, Ph.D., and HARRY T. CALVERT, B.Sc., The Yorkshire College. THE conversion of a tertiary aromatic base into a derivative of a secondary base has been observed by Hess (Ber., 1885, 18, p. 685), who found that, by boiling dimethylaniline with benzoic chloride, benzoylmethyl- aniline is formed, and the methyl group eliminated as methylic chloride. A similar reaction was described by Staedel (Bey., 1886, 19, 1947), who showed that acetic bromide converts dimethylaniline into acetyl- methylaniline. We find that the conversion of dimethyl- into monomethyl-aniline may be effected in quite another way. I n attempting to elucidate the constitution of the substance which we described a short time ago under the name of phenylnitrocarbinol (Trans., 1897, 71, 1050), we studied its behaviour with various substances, and found that, in most cases, its action closely resembled that of nitrous acid, which is scarcely remarkable, seeing that phenyl- nitrocarbinol evolves nitrous fumes on standing.Its action on dimethylaniline is, however, sufficiently curious to merit a brief description. On adding phenylnitrocarbinol to an equivalent quantity of dimet hyl- aniline, the mixture becomes very dark coloured, and the temperature rises rapidly, whilst at the same time there is a rapid evolution of nitrogen gas entirely free from carbon dioxide. This evolution of gas occurs whether the mixture is cooled down or allowed to become hot, and the quantity appears to be independent of temperature and, within certain limits, of the amount of dimethylaniline present, I n neither case are the yields given.M 2164 COHEN AND CALVERT: FORMATION OF In one experiment, 1 a001 5 grams of phenylnitrocarbinol and 2 grams of dimethylaniline gave 13.5 C.C. of gas, and, i n a second experiment, performed under similar conditions, 2.2225 gramsof the nitrocarbinol gave 27 C.C. of gas, the proportion of substance and gas being in both cases the same. The product of the action, which is deep red by t,ransmitted light and a deep green by reflected light, was mixed with sufficient hydro- chloric acid to combine with the unchanged dimethylaniline, and then extracted with ether. By adding sodium carbonate to the acid solution and distilling with steam, the unchanged dimethylaniline could be recovered ; the tarry liquid which remained in the distilling vessel did not invite further investigation.The ethereal extract contains benzaldehyde, benzylic alcohol, and nitrosomethylaniline. Four experiments, in each of which 30 grams of phenylnitrocarbinol were employed, gave on the average 5 grams of benzaldehyde, 4.5 grams of benzylic alcohol, and 5.5 grams of nitrosomethylnniline. Thus about half of the nitrocarbinol disappears, and is probably represented by the tarry material already referred to. That the nitrosomethylaniline is not due, as was a t first supposed, t o the presence of methylaniline in the dimethylaniline used, was shown by the fact that a sample of dimethylaniline which had been carefully freed from monomethylaniline gave a result precisely similar to the above.The three substances contained in the ether were separated and identified, as follows. The ethereal extract mas treated with sodium hydrogen sulphite solution until nothing further crystallised. The ethereal solution was then separated from the bisulphite compound, the ether removed by distillation, and the residue distilled with steam ; an oil of a yellow colour, and possessing the fragrant smell of nitroso- methylaniline, passed over, leaving a yellow, crystalline compound in the distilling flask, and this, when recrystallised from water, formed brilliant, golden plates which melted with decomposition at 150'. The minute quantity of this crystalline compound precluded its further investigation.The nitrosomethylaniline was extracted from the distillate by ether, the ether removed, and the residual oil warmed with 2$ times its weight of stannous chloride previously dissolved in three times the quantity of strong hydrochloric acid ; the nitrosomethylaniline is thus reduced to methylaniline and remains in solution, whereas the whole of the benzylic alcohol is converted into benzylic chloride and separates as an oil. The liquid is then diluted with water and distilled in a current of steam. The benzylic chloride which distils was identified by convert- ing it into benzaldehyde, and the latter into the phenylhydrazone melting a t 153'. The solution of methylaniline was made alkaline with caustic mda, extracted with ether, apd the ethereal solutiop,MONOMETHYLANILINE FROM DIMETHYLANILINE.165 after dehydrating over potash, was distilled ; the methylaniline thus obtained was then converted into the platinochloride, which gave the following result on analysis. 0.1358 gave 0.0438 Pt. Pt = 31-2 per cent. .It is difficult to formulate in any satisfactory fashion the above reaction. If we assume that the half, of the nitrocarbinol which is converted into tar, has been oxidised at the expense of the other half, then the equation (C7H,N),,H,PtC16 requires Pt = 31.4 per cent. 4C,H7N03 = 2C,H80 + 2C7H,0 + N, + 2N0 + 30, ?lienyli~itro- Benylic Benz- Given off Forming carbiuol. alcohol. aldehycle. as free nitrosoinethyl- nitrogen. aniline. will represent very closely the quantities involved.What becomes of the methyl group which is detached from the dimethylaniline cannot be a t present explained, seeing that no carbon dioxide is formed. The evolution of nitrogen is generally associated either with the action of a nitroso- on an amido-group or with the decomposition of a diazo-compound, which practically represents an intermediate stage of the same process. As there appears no reason to anticipate the formation of a diazo-compound, we are led to assume that the first process is responsible for the production of nitrogen. This could only occur by the reduction of an original nitro- or nitroso-group t o an amido-group, that is, by the reduction of the nitrocarbinol to benzyl- amine, which, by the action of nitrous acid evolved from another molecule of the nitrocarbinol mould produce benzylic alcohol, whilst benzaldehg de would be formed simultaneously.By what chemical change the reduction occurs, it is impossible at present to conjecture. Action of Nitroyen Trioxide on Dinzethylaniline. The above result suggested the possibility of a similar reaction occurring when nitrogen trioxide acts on dimethylaniline in a n in- diEerent solvent. A brief reference to the action of nitrogen trioxide on dimethylaniline dissolved in alcohol or acetic acid occurs i n a paper by Lippmann and Lange (Bey.: 1880, 13,2136), in which they state that the base is partly converted into a resinous matter (partidle Verharxung). Having a small quantity of the trioxide dissolved in chloroform a t hand, the gas was driven over into a solution of di- methylaniline dissolved in ether by a current of nitric oxide in order to remove traces of the peroxide. The ether rapidly changed colour, passing from green to black, and a black and sticky deposit ultimately separated.This method was afterwards modified, and liquid nitrogen166 FORMATION OF MONOMETHYLANILINE FROM DIMETHYLANILINE. trioxide" was allowed to drop into the dimethylaniline dissolved in five times its weight of dry ether, Each drop of the trioxide on coming in contact with the ether pro- duced a hissing noise like a red-hot wire plunged into water, but in spite of the apparent vigour of the action, there was a scarcely per- ceptible rise of temperature. I n both cases, the same result was obtained. I n order to test the product for nitrosodimethylaniline, the ether, which was coloured brown, was decanted from the black deposit, shaken with hydrochloric acid to remove dimethylaniline, the ether removed by distillation, and the residue distilled with steam.The aqueous distillate was yellow ; but no drops of oil were visible, and no smell of nitrosomethylaniline could be detected. The distillate was extracted with ether, and the minute quantity of residue left on removing the ether gave no nitroso-reaction. Nitrosodimethylaniline is therefore not formed by this reaction, and the action of nitrogen trioxide is distinct from that of phenylnitrocarbinol. I n the distilling flask, a small quantity of yellow, needle-shaped crystals separated, which were apparently identical with the substance obtained in the action of phenylnitrocarbinol on dimethylaniline, and previously referred to.The black, tarry-looking product, although of such an uninviting appearance, is nevertheless easily purified ; it was first extracted with small quantities of benzene until the latter was nearly colourless. A little resinous matter is thereby removed; and as prolonged boiling with alcohol decomposed the substance, the residue was repeatedly extracted with small quantities of alcohol just heated to boiling. On cooling, long, steel blue needles separate ; these decompose with slight explosion when heated, evolving nitrous fumes. The substance dis- solves readily in alcohol and in water with a bright yellow colour. On boiling with glacial acetic acid for a short time, a rapid evolution of nitrous fumes takes place, and the product, which contains nitrogen, when poured into water forms a yellowish-green, crystalline mass, con- sisting of fine needles.These, when recrystallised from dilute alcohol, are pale brown, and melt at 155-157'. As these products are readily obtainable, we have thought it worth while t o investigate more fully this somewhat curious reaction, which we reserve for a future communication. * The liquid trioxide is most conveniently prcpared by acting upon arsenic trioxide with ordinary concentrated nitric acid, whereby a considerable quantity of peroxide is formed, and allowing the gas to meet a current of pure and dry nitric oxide on its way to the cooled receiver. If a more dilute nitric acid is used, the yield is very much diminished, as the gas evolved consists mainly of nitric oxide. By operating in the manner described, the trioxide is obtained of a pure blue colour.FENTON : VOLUMETRIC ESTIMATION OF SODIUM. 167 It is interesting to note the entire dissimilarity between the action of anhydrous nitrogen trioxide and that of its aqueous solution, and it seems not unlikely that analogous results may be met with in the case of other bases, and possibly also in the case of phenols.

ISSN:0368-1645    

DOI:10.1039/CT8987300163

出版商:RSC    

年代:1898

数据来源: RSC

摘要:

FENTON : VOLUMETRIC ESTIMATION OF SODIUM. 167 XI.- Volumetiic Estirenution of Sodium. By HENRY J. HORSTNAN FENTON, M.A. Titrution of Dilbydroxytartaric Acid with Potccssiuna Permanganate. WHEN a few drops of potassium permanganate solution are run into a solution of dihydroxytartnric acid, mixed with excess of dilute sulphuric acid, a t the ordinary temperature, there is a t first no apparent change. After standing for a few minutes, however, the colour is discharged, and on continuing the addition of permanganate, the action, when once started, proceeds rapidly, the behaviour being in this respect analogous to that of hydrogen dioxide when similarly treated. The change becomes somewhat slower as i t approaches completion, but the end point is well marked and definite. The relation between dihydroxytartaric acid and permanganate will be seen from the following results.Using a solution of permanganate containing 3.200 grams KiMnO, per litre, Atonis of oxygen re- Gram acid taken. C.C. KNnO4. Gram IiJIiiOp quired for 1 mol. acid. 0.3160 99.7 0.31904 2.90 0.2932 92.3 0.29536 2.90 0.1409 44.2 0,14144 2-89 0.2506 78.6 0.25152 2-89 and with n solution containing 6.3374 KMnO, per litre, 0.3145 49.9 0.31624 2.89. Taking the mean of these five observations, 1 gram KMnO, = 0.99405 gram C4H608, or 182 grams C4H608= 183.09 grams KMnO,. If the acid were entirely oxidised t o carbon dioxide and water, 3 atoms of oxygen would be required for 1 molecule of acid C,H,O, + 3 0 = 4C0, + 3H20. The difference observed may be due, in part, to the fact that a n aqueous solution of the acid undergoes a slight decomposition, even a t ordinary temperatures, into tartronic acid and carbon dioxide.I n the experiments recorded in a former communication (Part I., Trans., Jan., 1 SSS), i t was observed that small quantities of carbon dioxide could be traced after the solution had been standing for about 10 or 12 minutes,168 FENTON : VOLUMETRIC ESTIMATION OF SODIUM. and this is about the usual duration of the experiment when titrating the acid with permanganate. It is true t h a t tartronic acid also reduces permanganate, but the initial stage, a t the ordinary temperature, is extremely slow. Thus 0.1625 gram of tartronic acid took about 50 minutes to bleach 1 C.C. of a solution of permanganate containing 0.0032 KMnO, per c.c.* In any case, the relation between dihydroxytartaric acid and per- manganate is a perfectly definite one, and it will be shown that the reaction affords a very convenient method for the estimation of the acid or its salts.Volumetric Estimution of Sodium. Bearing in mind the very sparingly soluble character of sodium dihydroxytartrate, and the definite relation between potassium per- manganate and dihydroxytartaric acid, it appeared probable that a simple method might be devised for the quantitative estimation of sodium by a volumetric process. I n the first experiments, measured volumes of a standard solution of pure sodium chloride were mixed with excess of dihydroxytartnric acid dissolved in a small quantity (about 10 c.c.) of water ; the mixture was made just ammoniacal and allowed to stand, with frequent stirring, for times varying from 10 to 75 ,minutes.The precipitated sodium salt was then collected, and after being drained with the aid of the pump was washed three times with small quantities of water, draining well each time ; the precipitate mas then dissolved off the filter with a considerable excess of dilute sulphuric acid, and the mixture titrated with permanganate. I n recording the results, it will be convenient t o denote the quanti- ties by the following symbols. cc = NaCl taken (gram) ; b = KMnO,, solution required (c.c.) ; c = N a found (gram) ; d = Na calculated (grim). I n the first trial experiment, the precipitation and washing were carried out at the ordinarp temperature. Strength of permanganate solution = 3.200 KMnO, per litre (sol.A). Strength of sodium chloride solution = 49.629 NaCl per litre. (6. b. c. d. 0.2481 4 114.2 0.0918 0.0975 * The difference is probably due also to traces of non-oxidisable inipurity (water or acetic acid, for example) in the samples of dihydroxytartaric acid employed, sincc subsequent experiments show that when the potassium salt is used instead of the free acid, the oxygen value approaches more nearly t o 3 atoms. The potassium salt lcrystallises extremely well, so that results obtained by its use are probably more trust- worthy. It will be seen, however, that the numerical value of the oxygen ratio in no way affects the final results in the estimation of sodium.PENTON : VOLUMETRIC ESTIMATION OF SODIUM.169 It has been previously shown (Part I.), in the experiments on titra- tion by alkalis, that the salts of dihydroxytartaric acid undergo a considerable amount of decomposition in contact with water a t the ordinary temperature, so that a low result was here to be expected. I n the following experiments, both the sodium salt and the di- hydroxytartaric acid solntions were carefully cooled by ice before mixing, the mixture was allowed to stand in ice during precipitation, and the precipitate was washed with ice-cold water. The advantage of operating at 0' is not only that the decomposition of the salt is prevented (as previously shown), but that the solubility of the sodium salt a t this temperature is exceedingly small. The solubility, as will be pointed out later on, is 0,039, a t Oo, that is, 100 parts of water dissolve 0.039 part of the sodium salt, which is equivalent to 0.0064 part of sodium, The total volume of the filtrate and washings in each experiment usually amounts to about 25-40 c.c., so that, even in pure water, the amount of sodium dissolved would be almost negli- gible ; but the solubility is of course still further diminished by the presence of excess of dihydroxytartrate, that is, in a solution con- taining a common ion.a. b. C. a. I. 0.24814 120.2 0,0966 0.0975 11. 0.24814 60.5 0,0963 0,0975 111 took 65.5 c.c., and I V took 60.6 C.C. of permanganate. I n 11, 111, and IV, a fresh solution of permanganate was now employed, containing 6.3375 KMnO, per litre (solution 13). The times of precipitation, in minutes, were 15, 25, 75, and 45 respectively. Although these results were constant and not much below the theoretical values, the process was hardly considered satisfactory, since, on further trial, it was found that excess of ammonia considerably vitiated the results, and exact neutralisation is not easy.Experiments were then made using pure potassium carboaate (prepared from potas- sium bitartrate) in calculated quantity for neutralisation in place of ammonia. The mixture was also made more concentrated, the acid being now dissolved in about 2 C.C. of water, instead of in 10 C.C. A fresh solution of sodium chloride was prepared containing 40 grams KaC1 per litre, the permanganate used being the same as in the previous experiments (solution B). Five C.C.of NaCl solution mere used, as before, for each experiment. a. b. C. a. v. 0*200 52.1 0.0815 0.0786 VI took 53 c.c., and VII 54 C.C. The times of precipitation Using twice the previous were 30, 60, and 150 minutes respectively.170 FENTON : VOLUMETRIC ESTIMATION OF SODIUM. proportion of dihydroxy tartaric acid and potassium carbonate? the results were still higher, VII taking 57.3 C.C. Substituting ammonium carbonccte for potassium carbonate, similarly high results were obtained, V I I I requiring 52.8 C.C. The explanation of these high results when potassium 01' ammonium carbonates are used in concentrated solutions is found in the fact, subsequently discovered, that potassium and ammonium dihydroxytartrates, although fairly easily soluble a t ordinary tem- peraturcs, dissolve with difficulty a t 0" and thus tend to contaminate the precipitated sodium salt.This source of error would be avoided, and the process much simplified, by employing one of these salts for precipitation instead of using the free acid and subsequently neutralising. The preparation and composition of the potassium and ammonium salts were therefore studied, with the results which will be given in a subsequent communication. The potassium salt is easy to prepare, and appears to be quite permanent if kept in a closed vessel (it is also fairly permanent in the air, *for some days, a t any rate). It is likewise somewhat less soluble than the ammonium salt, so that its use does not involve any danger of contamination with ammonium, should salts of the latter be present.The potassium salt is, in fact, a most cocvenient reagent both for the qualitative and quantitative estimation of sodium. Using the same sodium chloride and permanganate (B) solutions as before, and precipitating with excess (about 18 equivalents) of the potassium salt, the following resulk were obtained. a. b. C. d. 0.3 30 49.4 0.0786 0.0786 0.200 48.4 0,0770 0,0786 0.200 48.8 0.0776 0.0786 Since measurement of the strong sodium chloride solution was probably hardly sufficiently accurate, in the next experiments weighed quantities of sodium chloride? each dissolved in 5 C.C. of water, were employed instead of measured volumes of standard solution. a. b. C. d. 0.0997 23.5 0.03'74 0.0391 0.1915 47.6 0.0757 0.0752 0.4367 107-4 0.1710 0.1716 The process, therefore, when conducted in this manner, evidently gives satisfactory results.The permanganate solutions employed so far had been standardised by means of ammonium oxalate, and the results were calculated from the relations shown t o exist between permanganate, dihydroxytartaricFENTON : VOLUMETRIC ESTIMATION OF SODIUM. 171 acid and sodium. I n preparing a fresh permanganate solution (solution C) for subsequent experiments, i t appeared that the most direct way would be to standardise the solution by means of pure sodium chloride. X= strength of permanganate (C) in grams of Na per Eitre. The following were the observations. a. b. S. 0.2235 49 *4 1-778 0.1865 40.4 1.814 0.3704 79.9 1.822 0,3032 66.2 1 *so0 Mean of the four experiments, S= 1,805. This solution was now employed for the estimation of sodium in various common sodium salts.Nornaul Sodium XuJphnte.-'l'his was a commercially pure specimen recrystallised and ignited. 0.3472 gram of substance, dissolved in about 5 C.C. of water and precipitated with excess (1 gram) of potassium di- hydroxytartrate, required 62.75 C.C. of permanganate (C). Na Found = 32.62 per cent., Calculated 32.39 per cent. #odium 21Titrute.--Commercjally pure specimen recrystallised and dried a t 100'. 0.3641 gram of substance in about 5 C.C. of water pre- cipitated with 1.3 grams of potassium salt, required 55.2c.c. of per- manganate (C). Na Found = 27.36 per cent., Calculated 27.05 per cent. Mixture of Sodium Chloride and Magnesium SuZphate.-Magnesium sulphnte gives no precipitate with potassium dihydrouytartrate.0.2307 gram NaCl mixed with 0.3 gram MgS0,,7H20 dissolved in about 7 C.C. of water and precipitated with 0.8 gram of potassium salt, required 50.3 C.C. permanganate (C). Na Found = 39.35 per cent., Calculated 39.31 per cent. The presence of magnesium, therefore, does not interfere with the accuracy of the sodium estimation. Mixture of Sodium Chloride and Ammonium C?doride.-O*3225 gram NaCl mixed with 0.4 gram NH,C1 dissolved in about S C.C. of water and precipitated with 1.1 grams of potassium salt, required 67.95 C.C. of permanganate (C). Na Found = 38-03 per cent., Calculated 39.31 per cent. From this result, it would appear that the presence of excess of ammonium salt tends t o give low results in the sodium value. Rochelle Salt.-Commercially pure specimen : pressed.1.256 9 gram of substance precipitated with 1.2 grams of potassium salt, required 54.85 C.C. of permanganate (C). Na Found = 7.87 per cent., Calculated 8.15 per cent. Sodium salts of weak acids whose solutions give an alkaline reaction172 FENTON : VOLUMETRIC ESTIMATION OF SODIUM. with litmus, such as phosphate and acetate, give somewhat low results when precipitated by means of the potassium salt. But withfree di- hydroxytartaric acid, such salts give normal, or nearly normal, results. This is probably due t o the instability of sodium dihydroxytartrate in presence of alkalis, a fact which was indicated in the low results obtained in presence of free ammonia, and in the action previously mentioned of sodium hydroxide (Trans., 1898, 73, 74).Free dihydroxytartaric acid gives a precipitate with all sodium salts which have been examined, with the exception of the borate (see below). 'Even salts of strong acids, such as sulphate, chloride, and nitrate, are, on standing, partially precipitated, and in the case of weaker acids, the precipitation appears to be complete, or nearly so. It is possible that the relative avidities of many acids might be compared in this manner, Sodium Acetate.-A commercially pure specimen recrystallised and pressed, I. 0.4014 gram substance dissolved in 5 C.C. water and precipitated with 1.05 grams of potassium salt, required 36.65 C.C. of permanganate (C). 11. 0.6458 gram substance dissolved in 5 C.C. of water and precipi- tated with 0.5 gram of free dilqdyoxytartnric acid required 60.9 C.C.of permnnganate (C). Na Found = 16.98 per cent., Calculated 16.91 per cent. Sodium PlLosphete.-A commercially pure specimen recrystallised and pressed. I. 0.8664 gram substance dissolved in 10 C.C. of water and precipi- tated with 1.2 grams of potassium salt, required 58.4 C.C. of per- manganate (C). Na Found = 13.16 per cent. 11. 1.0814 gram substance dissolved in 10 C.C. of water and pre- cipitated with 1 gram of free dihydroxytartaric acid required 73.8 C.C. of permanganate (C). Na Found = 12.31 per cent., Calculated 12.84 per cent. Sodium Carbonate.-This gives low results, even with the free acid. This is probably due to the difficulty of preventing loss by spirting without unnecessary dilution of the solution, by washing, and perhaps also t o the difficulty of preventing a rise of temperature during neutralisation.With the potassium salt as precipitant, 38.68 per cent. Na was obtained, and with the free acid 42.85 per cent., theory requir- ing 43-43 per cent. Carbonates should, therefore, be first acidified, say, by hydrochloric acid, with due precautions against loss by spirting, the solution evaporated to dryness, and the residue dissolved in a small quantity of water. Borax. -This salt is altogether exceptional in its behaviour, since its solution gives no pecipitate whatever, either with the potassium Na Found -L 16.48 per cent.FENTON : VOLUMETRIC ESTIMATION OF SODIUM. 173 salt or with the free acid. I n this respect, it differs from all other sodium salts which have been examined.The reason for t h i s difference is under investigation. Possibly, as with some other hydroxy-acids (for example, tartaric and salicylic), a compound is formed, which is soluble in water. Boric acid, if present, must therefore be removed by one of the usual methods, such as by methylic alcohol and hydrogen chloride, before sodium is estimated. Directions for Working the P?*ocess. I n order to ensure accurate results, attention must be given to the following details. Metals other than potassium, sodium, and magnesium must be absent. (Possibly some other metals may prove to be admissible, but only a few have been examined. Ammonium salts, if present in any quantity, appear to produce low results, so had better be removed.) The metals should be present preferably as chlorides, sulphates, or nitrates.The solution to be examined must be concentrated and neutral. Potassium dihydroxytartrate, K,(C,H,O,),H,O, is dissolved in the least quantity (about 30 times its weight) of ice-cold water. The salt dissolves with some difficulty, and the solution, if not completely clear, is filtered before use. Both solutions having stood in melting ice for a few minutes, the potassium salt is added in excess, the mixture kept in melting ice for half an hour, with occasional stirring, and the precipitated sodium salt, after being collected on a small filter, is drained with the assistance of the pump, and quickly washed three or four times with small quantities (about 4 or 5 c.c.) of ice-cold water, draining each time.The precipitate is then dissolved off the filter with a large excess of dilute sulphuric acid, and the solution titrated with potassium permanganate at the ordinary temperature of the laboratory. The permanganate may be standardised by the usual methods (by oxalic acid or ammqnium oxalate) and the result calculated from the relation which is shown to exist between permanganate and dihydroxy- tartaric acid ; but the simplest and best method is to standardise the permanganate indirectly by means of pure sodium chloride, proceeding exactly as above directed. If salts of weak acids, which give an alkaline reaction, such as acetates or phosphates, are to be examined, the free acid should be substituted for the potassium salt. Carbonates or hydroxides must first be neutralised, and boric acid, if present, must be removed by one of the usual methods, such as by methylic alcohol and hydrogen chloride, The results obtained appear to be as accurate as can be expected from174 HEWITT AND POPE: any volumetric process of the kind.The method could, of course, be varied in several ways. For instance, a measured excess of potassium dihydroxytartrate might be employed and the excess estimated after precipitation. Or the sodium salt could be determined gravimetrically by converting it into sulphate, chloride, &c., or it could be heated with water and the carbon dioxide estimated. This volumetric process is probably much more economical than the estimation of potassium by platinnm chloride; it is certainly very much more rapid, and probably quite as accurate, so that in the case of a mixture consisting entirely of potassium and sodium salts, where it is desired to estimate one of the metals only, it would be more advantageous to determine the sodium than the potassium.* Qualitative Detection of Xodium. I n a former communication (Trans., 1895, 67, 48), the use of free dihydroxytartaric acid was proposed as a reagent for the detection of sodium, the solution to be examined being mixed with a solution of the acid, neutralised with ammonia, and the mixture stirred, preferably on a watch-glass. The potassium salt, however, affords a far more convenient reagent, since the necessity for neutralisation is dispensed with, and the introduction of ammonia is avoided ; it was shown above that the presence of ammonia and of ammonium salts tended to give low results in the sodium value, so that for qualitative detection of small quantities its presence is objectionable. By using ice-cold solutions of the potassium salt and of the substance to be examined, and keeping the mixture for some time at Oo, it is fairly easy to detect one part of sodium in over 2000 parts of water.

ISSN:0368-1645    

DOI:10.1039/CT8987300167

出版商:RSC    

年代:1898

数据来源: RSC

摘要:

174 HEWITT AND POPE: XIL-Derivcctwes of B?.omotolyllzyd?.oczi~ae? C,H,Br(CH,)(N,H,) [I : 3 : 61. By J. T. HEWITT, M.A., D.Sc., Ph.D., and F. G. POPE. SEVERAL years ago, one of the authors described orthochlorophenyl- hydrazine and several of its derivatives (Trans., 1891,59, 209 ; 1893, 63, 868). It was hoped that, under certain conditions, some of the * Wishing to test the working of the process in other hands, I asked one of our students, Mr. H. Jackson, of Downing College, to determine the sodium in a sample of pure sodium chloride. Proceeding according to the instructions given above, and using tho permanganate solution C, he obtained the following result : 0,2765 gram substance required 60.2 O.C. of permanganate. Na found = 39'29 per cent., Calculated 39'31 per cent,DERIVATIVES OF BROMOTOLYLHYDRAZINE.17 5 derivatives of this hydrazine might lose hydrogen from the side chain and halogen from the nucleus, forming closed ring compounds, but no results of any value in this direction were obtained, and the problem remained as to whether bromine compounds might not be more suitable for such syntheses. Orthobromaniline, however, is comparatively diffi- cult to obtain pure, whereas orthobromoparatoluidine can be prepared in any quantity by Wroblewsky's method (Annulen, 1873,168,153). The paratoluidine is first converted into acetoparatoluidide, the finely- powdered crude product (105 grams) is mixed with a large excess of cold water (1 litre), and the calculated amount of bromine (1 16 grams) run slowly into the mixture with continual stirring; the mixture is now raised to boiling, allowed t o cool, and the supernatant liquor run off the cake of orthobromacetoparatoluidide.The hydrolysis is readily effected by boiling the product with five times its weight of hydrochloric acid (2 vols. HUl: 1 water); on cooling, the hydrochloride of ortho- bromoparatoluidine separates out almost completely, and may be recrystallised from hot dilute hydrochloric acid. This hydrochloride is converted into the corresponding hydrazine hydrochloride by the methods proposed by Victor Meyer and Lecco (Bey., 1883, 16, 2976) and by Bamberger (Bey., 1896, 29, 1834); but as the former method gives better yields, we have used it exclusively. It is preferable to work with small quantities at a time. The finely powdered orthobromoparatoluidine hydrochloride (22 -25 grams), mixed with 10 times its weight of fuming hydrochloric acid, and cooled by ice and salt, is diazotised by the gradual addition of sodium nitrite (7 grams) dissolved in water (30 c.c.); after being left for 1 hour in the freezing mixture, it is poured, with continual stirring, into a solution of stannous chloride (37.8 grams) in its own weight of fuming hydrochloric acid kept well below 0".During conversion of the diazonium into hydrazine salt, it is necessary t o keep the temperature low,and i t is advisable to pour the diazo-solution into the stannous chlor- ide, otherwise the heat developed is liable t o decompose the diazonium salt, with production of tarry products. The double tin salt of the hydr- azine obtained is collected, and after drying on porous tiles, is dissolved in boiling water and freed from tin by bydrogen sulphide ; on concen- trating the clear solution, the hydrazine hydrochloride is deposited in colourless needles.An aqueous soliltion of this salt shows the characteristic reduction of Fehling's solution. Analysis.-C7H6Br*NH*NH2,HC1 requiresN = 11 *79 per cent. Found N = 11.51. The purified salt melts at 190" with slight evolution of gas. The free hydrazine can readily be obtained by precipitating ft solution of176 HEWITT AND POPE: the hydrochloride with ammonia ; after recrystallisation from ether, it is obtained in beautiful, colourless, silky needles melting a t 91". AnaIysis.-C7H,Br*NH*NH2 requires N = 13.93 per cent, Found N = 13 96 per cent.Salts of the hydrazine were prepared by dissolving it in ether, and adding ethereal solutions of the corresponding acids. The mitrate separates from the ethereal solution in radiating masses, SO that the liquid is soon filled with a paste of crystals, white and pearly in appearance ; after being dried on a porous tile, they melt at 154' with slight decomposition. Analysis.-C7H,Br*NH*NH2,HN0, requires N = 15.91 per cent. Found N = 15.29 per cent. Xu1phate.-This was prepared in a similar manner, but an excess of acid had to be avoided or the sulphate and excess of acid separated as a heavy oily layer. By recrystallisation from boiling water, the suIphate was obtained in long, colourless needles easily soluble in bot, but only sparingly in cold, water, and melting a t 201".Analysi~.-(C~H,~r*~,H~)~,H~~~, requires so, = 19-20 per cent. Found SO,= 19.22 per cent. The oxalate was immediately precipitated as a colourless, crystalline paste on mixing ethereal solutions of the hydrazine and anhydrous oxalic acid ; the product was collected, dried on a tile, and recrystallised from boiling water, in which it dissolves fairly when hot, but only very slightly when cold. It separates in small, colourless prisms soluble in hot alcohol, and melting a t about 150°, the exact tempera- ture depending on the rate of heating; decomposition takes place apparently, the molten mass frothing, although it still remains colourless, so that probably the reaction consists in the formation of a hydrazide. Analysis.-(C7H,Br*N,H,),,C,0,H2 requires N = 11 *39 per cent.Found N = 11.64 per cent. Besides the above salts, we have characterised the hydrazine by converting it into a number of derivatives. AcetylbromotolylJ~yds.azine was prepared by boiling the hydrazine with excess of glacial acetic acid for some hours in a reflux apparatus; the product was then poured into water, collected, and recrystallised twice from dilute acetic acid. It forms small, thick prisms melting a,t 124". Analysis.--C7H6Br*NH*NH*CO*CH, requires N = 11.53 per cent, Found N = 11.77 per cenl;. The composition was confirmed by a nitrogen estimation.DERIVATIVES OF RROMOTOLYLEYDR~AZINE. 177 This acetyl derivative dissolves slightly in hot, but is practically insoluble in cold, water ; i t is also insoluble in light petroleum, and in benzene and its homologues.It is taken up sparingly by ether, dissolves in alcohol and glacial acetic acid, and is dissolved with great readiness by chloroform. Rromotolylsemicccr6axide was immediately precipitated on mixing aqueous solutions of the hydrazine hydrochloride, and potassium cyanate in molecular proportion. It was collected, washed with cold water, and recrystallised from a large quantity of boiling water, in which it is only sparingly soluble ; it is nearly insoluble in cold water. Bnalysis..-C7H,Br*NH*NH*C0.NH, requires N = 17.21 per cent. Found N = 17.14 per cent. This semicarbazide is insoluble in light petroleum and benzene ; dissolves somewhat in chloroform, and is readily soluble in ether, acetone, and glacial acetic acid. Bromotolylallyltl~iosemica~baxide was obtained by mixing ethereal solutions of allylthiocarbimide and the hydrazine in molecular propor- tion ; on evaporating the ether, the thiosemicarbazide was left as an oil, which, on long continued stirring, solidified to a hard mass.On recrystallisation from alcohol, it was obtained in colourless prisms, the faces of which are often striated, the prisms themselves being frequently united in clusters. The ends of the prisms were usually badly developed. A sulphur estimation gave S = 11.55 per cent. C?H,Br*NH*NH*CS*NH*C::H; requires S = 11.23 per cent. It melts a t 163'. This semicarbazide melted at 136*5", and showed no signs of the isomerism observed by Marckwald in compounds of a similar type. It dissolves in alcohol, ether, ethylic acetate, acetone, benzene, carbon bisulphide, and glacial acetic acid, but is insoluble in light petroleum.On adding copper sulphate solution to the ethereal solution, the latter becomes yellow, and turns a very dark olive brown on adding ammonia. BromotolyZpiLenylthiosemica~~~~i~~ was obtained in like manner, using ethereal solutions of the hydrazine and phenylthiocarbimide. On evaporating the ether, an oil was left which solidified on stirring it up with a small quantity of light petroleum. Dried on a porous tile, it melted almost completely about 122-1 25O, but after crystallisation from hot alcohol and drying at looo, the melting point mas found to be 142". The substance, when somewhat rapidly deposited from alcohol, forms t u f t s of prisms, whilst by slower evaporation the prisms are obtained singly and are all terminated with well-defined oblique faces.Analysis.-C7H,Br*NH*NH*CS*NH*C,H, requires S = 9.52 ; Br = 23.81 per cent. Found S = 9.55 ; Br = 22.63 per cent, VOL. LXXIII. N178 HEWITT AND POPE: As t o whether the above-mentioned behaviour of the substance on heating is to be ascribed to isomerism in the sense indicated by Mai-ck- mald (Be?.., 1892, 25, 3098) in the case of diphenylthiosemicarbazide, me cannot say ; it is, however, strange that, on mixing solutions of pure hydrazine and allyl- or phenyl-thiocarbimide and evaporating, the respective thiosemicarbazides should be obtained as viscous liquids which do not readily solidify. The substance is easily soluble in cold chloroform and acetone, and in warm alcohol, and fairly so in ether ; but benzene, toluene, xylene or amylic alcohol take it up easily, It does not dissolve very easily in concentrated sulphuric acid, and in ammonia, even if warm and concen- trated, but very sparingly, if at all.Warm' dilute soda solution takes it up easily, but it is reprecipitated by hydrochloric acid. The thio- semicarbazide is turned superficially red by the vapour of fuming nitric acid ; in actual contact with the fuming acid, it catches fire. ~~c~~~raZdehydebrol?totolyll~ydraxone.-Furfuraldehyde (1 gram) in a small bottle, was covered with water, and a solution of the hydrazine hydrochloride (2.5 grams) added; on adding a solution of sodium acetate, the hydrazone was precipitated as an oil which obstinately refused to solidify, but after a month it became nearly solid, and on washing with a little alcohol and stirring, complete solidification was induced.When slowly crystallised from warm alcohol, it was deposited in well-defined, brown needles which melted a t 87'. Analysis.-C,H,0*CH:N*NH*C7H6Br requires N = 10.03 per cent. Found N = 9.77 per cent. Furf uraldehydebromotolylhydrazone dissolves easily in ether, ethylic acetate, chloroform, acetone, and glacial acetic acid, but is insoluble in light petroleum. BenxaldehydebromotolyZiLydraxone, prepared in a siinilar manner, sepa- rated a t first as a pale yellow oil, which, however, on vigorous shaking, was suddenly transformed to a nearly colourless, crystalline mass ; by recry stallisation from alcohol, it was obtained in well-defined, colourless, rhomboidal plates which melted a t 84'; the alcoholic solution frequently shows the phenomenon of supercooling.Benzaldehydetolylhydrazone dissolves in ether, chloroform, ethylic acetate, benezene, and glacial acetic acid, but is insoluble in light petroleum. Analysis.-C,H,*CH:Pr'*NH*C7H6Br requires N = 9.69 per cent. Found N = 10.11 per cent. ~~~ZicylaldehydebromotolyZ~ydrccxorte.--The free hydrazine liberated from 4 grams of the hydrochloride by 2 grams of sodium acetate was collected, washed, and dissolved in alcohol ; on adding the calculated quantity (2 grams) of salioylaldehyde, a brownish oil separated imme-DERIVATIVES OF RROMOTOT,YT,HYDRAZINE. 179 diately, and this, after the supernatant liquid had been removed, be- came solid on stirring vigorously with some light petroleum.The crystalline mass, after being washed with light petroleum and re- crystallised successively from ether and alcohol, was obtained in long, straw-coloured needIes which melted a t 109'. Analysis. -OH* C,H,* CH:N*NH* C7H,Br requires N = 9.18 per The salicylaldehydehydrazone dissolves in ether, acetone, chloroform, ethylic acetate, carbon bisulphide, benzene, and glacial acetic acid, but only sparingly in alcohol, and is insoluble in light petroleum. Pyvuvic acid 6~omotolyZhydvccxone is completely precipitated by mixing aqueous solutions of the hydrazine hydrochloride and pyruvic acid ; the pale yellow flocks thus formed, after being washed and re- crystallised from hot dilute alcohol, are obtained in bright yellow crystals which melt a t 175' to 5t clear yellow liquid, some gas being evolved.The substance is soluble in chloroform, ether, acetone and glacial acetic acid, but insoluble in benzene and light petroleum. Analysis.-C7H,Br*NH*N: C(CH,)*COOH requires C = 44.28 ; H = 4.06 per cent. EthyZic pyuvate bromotoZyZiLyd~(~xo?ze was prepared by boiling the acid for 2 hours with an equal weight of concentrated sulphuric acid and 10 times its weight of alcohoi, using a reffux apparatus. The mixture was then poured into a dilute solution of sodium carbonate, allowed to stand overnight, and the substance collected, washed, and dissolved in alcohol ; on allowing the solution to evaporate slowly, the compound was deposited as tufts of slightly yellowish needles. cent.Found N = 9.08 per cent. Found C = 44-30 ; H =: 4.09 per cent. Analysis.-C7H,~3r*NH.N: C(CH,)*COOC,H, requires N = 9.36 per It softens about 7.5" and melts a t 84-85'. It is easily soluble in the usual solvents. Various salts of this acid were prepared, in the hope of eliminating the metal in union with bromine, on heating, and so possibly obtaining closed ring derivatives. As the experiments in this direction have not as yet yielded very satisfactory results, we have decided to publish the remainder of our work now, and leave this portion for a future com- munication. Thepotnssiunt scdt was prepared by mixing the acid with the calcu- lated quantity of pure anhydrous potassium Carbonate, adding water, and warming until the evolution of carbon dioxide had ceased.Enough water was then added to dissolve all the salt on boiling, and the solution, filtered hot, was allowed to cool; the salt then separated in cent. Found N = 9.83 per cent. N 2180 DERIVATIVES OF RROMOTOLYLHYDRAZINE, fern-like aggregates, which were collected with the aid of the pump, washed with alcohol, and air-dried. Analysis.-C7H,Br*NH*N: C(CH,)*COOK + 3H20 requires H20 = 14.60 ; K = 10.74 per cent. Found H,O = 14.56 ; K = 10.33 per cent, The ammonium salt was obtained by dissolving the acid in hot dilute ammonia; the crystals deposited on cooling are, like those of the potassium salt, not very soluble in cold water. Analysis.-C,H,Br*NH*N: C(CH,)*COONH, requires N = 14-58 per cent. The aqueous solution of this salt gives precipitates with solutions of salts of the heavy metals.The precipitate with silver nitrate be- comes violet coloured on drying, and decomposes readily on heating. The analysis of the dried salt showed that considerable decomposition had taken place, it contained 34-56 per cent. of silver, whilst the salt C,,H,,BrN202Ag should contain 28.57 per cent. The lead salt is a pale yellow, amorphous powder ; dried a t 105O, i t gave a percentage of lead agreeing with the theoretical numbers. Analysis.-[C7H,Br*NH*N: C(CH,)COO],Pb requires Pb = 27.71 per cent. Action of Heat on these Sdts.-The anhydrous potassium salt, when heated gradually, remains unchanged below 2 15O, but at this temperature, a brisk reaction takes place, the salt melts, the mass darkens and froths up, and small quantities of liquid distil up the sides of the tube. On cooling and extracting the melt with hot water, the aqueous solu- tion was found to contain potassium bromide; the insoluble portion yields extracts both with dilute hydrochloric acid and dilute soda. It is thus seen that both a basic and acidic (or a t least phenolic) sub- stance are formed during the change ; their nature has, however, not yet been determined. The lead salt decomposes a t about 160' or 170". Much lead bromide is formed, and again both acid and basic products can be detected, A. similar decomposition takes place, and apparently more smoothly, by heating the lead salt with an indifferent hydrocarbon solvent for some hours in sealed tubes at 180'. We hope to shortly return to this subject, and lay the results obtained before the Society. Found N = 14.40 per cent. Found Pb = 28.05 per cent. EAST LONDON TECHNICAL COLLEGE,

ISSN:0368-1645    

DOI:10.1039/CT8987300174

出版商:RSC    

年代:1898

数据来源: RSC

摘要:

RIONO-, DI-, AND TRI-CHLOHBCETYL CROUPS, ETC. 181 x IlI.-EJect of the Moiao-, DG9 and Tyi-chloracetyl Grozqjs o f i the Rotatory Power of Methylic and Etlzylic Glycerates a d Taytrates. By PERCY FRANKLAND, F.R.S., and THOMAS STEWART PATTERSON, Ph.D., Late Priestley Scholar in Mason University College, Birmingham. THE effect of attaching halogens to the asymmetric carbon-atom has been the subject of numerous researches in which chlorine or bromine is substituted for the hydroxyl group of an optically active compound. I n the earlier investigations of this nature, the substitution mas effected by the action of the halogen acid, with the result that the halogen compound obtained was invariably inactive. Thus, from I-malic acid and hydrobromic acid, Kekulk (Ann., 1864, 130, 25) ob- tained only inactive bromosuccinic acid ; from Z-mandelic acid and hydro- chloric and hydrobromic acids, Easterfield (Trans., 1891, 59, 71) obtained only inactive chloro- and bromo-phenylacetic acids ; similarly, from active ( I and d ) isopropylphenylglycollic acids, Fileti (J.p . Chem., 1892, 46, 562), by the action of hydrochloric acid, obtained inactive isopropylphenylchloracetic acid only. The uniformity of these results not unnaturally led to the impression that such intro- duction of the halogen atoms must necessarily be attended with racemisation, and even gave rise to a suspicion that possibly the mere difference in the four groups attached to the carbon atom was not in itself sufficient to cause optical activity (Hantzsch, Grundriss d. Xteceochenzie). The incorrectness of these views has been more recently dem0nstrate.I by Le Be1 (Bull.SOC. chim., [iii], 1893, 9, 674), and more especially by Walden (Ber., 1895, 28, 1297), who, by acting with the halogen compouiids of phosphorus on the ethereal salts of malic, tartaric, lactic, and mandelic acids, has obtained active ethereal salts of bromosuccinic, bromomalic, chloro- and bromo- propionic, chloro- and bromo-phenylacetic acids, whilst these results have been further extended by J. Wallace Walker (Trans., 1895, 07, 914) in respect of chloro- and bromo-propionic acid. I n the substitutions by chlorine and bromine referred to above, it is very noteworthy that the sign of the rotation is reversed by the introduction of the halogen, a result which is contrary to what takes place when substitution in the same compounds is made by most other groups. This circumstance led to the idea that there mas something anomalous in the rotatory effect of the halogen atom attached to the asymmetric carbon atom.It has, however, been shown by Walden (Bey., 1895, 28, 2766; 1896, 29, 133) that the change in sign in the case of the ethereal salts of d-chloro-182 FRANKLAND AND PATTERSON : EFFECT OF THE CHLORACETYL succinic acid obtained from the I-malic salt is due t o a most re- markable transformation, for on regenerating malic acid from the d-chlorosuccinic acid, it is d-malic, and not Lmalic, acid which is obtained, and a similar transformation has been shown to take place by Purdie and Williamson (Trans,, 1896, 69, 837) in passing from the lzvorotatory lactic to the dextrorotatory chloropropionic ether, the latter, on removal of the halogen, yielding the dextrorotatory lactic compound.It is thus evident that the chloro- and bromo-compounds redly corresponding to the tartaric, malic, and lactic compounds from which they are derivable, and in which the halogen is attached t o the same bond of tlie asymmetric carbon atom as that t o which the original hydroxyl group of the parent substance was united, have a rotatory power of the same sign as the particular parent substance in question. The above results all refer to the effect of uniting the halogen directly to the asymmetric carbon atom, and a t the time our experi- ments were commenced there existed, so far as we are aware, only a few isolated observations of Le Bel’s (Zoc.cit.) and of Walden’s on the rotatory effect of halogen-atoms not so directly attached. The follow- ing is the extent of the observations made by Le Be1 on this subject. Propylene glycol, CH,*CH(OH)*CH,*OH, u = - 1’ 57’ ( I = 22 cm.). Propylene glycol diacetate, CH,*CH(O~C,H,0)*CH2*O*C2H30, a = - 8 Propylene glycol monochlorhydrin, u == - 53‘ ( I = 22 em.). Propylene glycol dichlorhydrin, a = - 23’ ( I = 10 cm.). Propylene glycol chlorobromhydrin, CH,* CHBr*CH,Cl, a = - 38’ ( I = 10 cm.). Propylene glycol chloracetin, CH,* CH(O*C,H,O)*CH,Cl, u = -I- 1’ 18’ ( I = 22 cm.). Propylene glycol chlorochloracetin, CH,* CH(C2H2C10,)*CH2C1, a = + 49’ ( I = 10 cm.). Propylene glycol chlorobutyrin, CH,* CH(O*CO*C,H7)*CH,Cl, a= + 27’ ( I = 10 cm.).From the above it will be seen that propylene glycol chloracetin has iiearly the same rotation as propylene glycol chlorochloracetin, so that in this case the substitution of chlorine for hydrogen a t a point remote from the asymmetric carbon atom does not very materially affect the rotation. The observationswhich had been made by Walden (Zeit.phys%cbl. Chem., 1895, 17, 264) referred t o the rotation of some monochloracetyl- and monobromacetyl-malates, a full summary of which will be found in ft paper by one of us (Trans., 1896, 69, 122). Again, more recently still, since the work recorded in this paper (Z=22 cm.).GROUPS ON THE ROTATORY POWER OF GLYCERATES, ETC. 183 was performed, some compounds have been prepared by Guye and Chavanne (BUZZ.SOC. chim., [iii], 1896, 15, 177--195, 275-305) which have a bearing on the same subject. Amylic alcohol ........................ [ u]y"= - 4'52" [ a ] y = - 4-12' , , acetate ....................... [ a]tOo = + 2 -53 [ a ] F = +2'51 , , propionate .................. [ u]? = + 2.77 [a]"d;"= 4-2.68 , , monochlorace tate ......... [a]ip= + 3'44 [a]y= t-3'36 ,, dichloracetate ............ [a]i2= -t 2.77 [a]:o'= +2.65 ,, trichloracetate.. ............. [.I2: = + 2.71 [a]:'= + 2.58 It was with the object of extending this knowledge of the rotatory effect of the h dogen-substituted fatty acid radicles that our inve3tiga- tiou was uridertakeii, b u t before its completion the rebults of a some- what similar iuyuiry were published by Freundler (Bull. SOC. cl~im., [iii], 1895, 13, l055), mliohe experimrlits are, however, limited to an examiri &ion ot the ir,ethj lw, e t h y tic, propylic, aud is0 j u t ) lic salts of dimouochlora etyltartiLric acid.Our investigations, there1 ore, only overlay in the matter of the preparation and study of two single com- pounds, to which special attention will be directed later on. , , monocliloropropionate ... [ u]i2 = + 3 *03 I. TRICHLORACETYL DERIVATIVES. Pyepcwation of Tvichlomcetyl Cldoyide.-This was effected by utilis- ing Friedel's reactiou in the manner described by Friederici (Bey., 1878, 11, 1971). A mixture of 100 grams of trichloracetic acid and 150 grams of phosphoric anhydride was heated at about 200' in a Wurt'z flask of about 2 litres capacity and dry hydrogen chloride passed into the flask above the surface of the mixture.The lateral tube of the flask was connected with a U-tube surrounded with ice and provided with a tubulure below, passing into a small flask in which the condensed liquid was collected. Only slight charring took place, and a good yield of chloride mas obtained, but the process is slow, two or three days being required for the preparation of 60-70 grams. The chloride was fractionated, using a Hempel tube, and was ultimately obtained almost entirely free from phosphorus compounds. We adopted this method of preparation for all the three chloracetyl chlorides in consequence of its being the only one which yielded a product very nearly free from phosphorus compounds. Ethylic Di-trichZoracetyZgEycerate.-This was prepared by allowing 16 grams of ethylic glycerate (a, = - 11-47' in 100 min.tube at 12') to drop slowly into 130 grams of trichloracetyl chloride a t loo", the mixture being maintained at this temperature for about 2 hours, and frequently shaken, a method which waa adopted in the preparation of nearly a11 the other ethereal salts described in this paper. The product was theii184 FRANKLAND AND PATTERSON : EFFECT OF THE CHLORACETYL submitted to distillation under diminished pressure, the excess of tri- chlorncetyl chloride passing over at 45-50', a first fraction was collected at 198" and a second a t 198-205". The first fraction was again treated with trichloracetyl chloride, and on distilling as above a frnc- tion was collected between 200' and 205", and this was mixed with the 198-205" fraction of the first distillation.This mixture was then refractionated until the rotation of the product became practically constant. I n this way, 9 grams of substance, boiling a t 202' under about 15 mm. pressure, and with the oil-bath at 240", were obtained. The following chlorine determinations were made by Carius' method. 1. 0.7466 gave 1.4976 AgC1. Cl=49-65 per cent. 3. 0.5608 ,, 1,1354 AgC1. Cl=50.06 ,, 3 . 0.565'7 ,, 1.1360 AgC1. C1=49*67 ,, 4. 05200 ,, 1.0406 AgCl. C1=49*50 ., 5. 0.5651 ,, 1.1340AgCl. Cl=49*64 .. C,H,O,CI, requires C1= 50.1 1 ycr C C ~ I L . The rotation was determined a t the following temperatures. Temp. 12.5' 98 77 60 48 42.5 12.6 Observed rotation in 44 nim. tube. - 12.73" - 11-89 - 12.19 - 18.28 - 11.68 - 12.08 - 12.66 Density compared with water at 4".[.In LSI,,* 1.5502 - 18.66' 1.4438 - 18.39 - 176.6" 1.4702 - 18.38 - 178.7 1.4925 - 18.39 - 180.6 1.5060 - 18.39 - 181.9 1.5127 - 18.40 - 182.8 1.5502 - 18.56 - 186.1) The density determinations actually made were d 12'/4'= 1.5502. d 60'/4*= 1.4915. ~l 100°/4'= 1.4413. Methylic Di-tricl~rorncetylgZycernte.--Twenty grams of methylic gly- cerate (a= - 6.30' in 100 mm. tube at 13.3') were slowly added to an excess of trichloracetyl chloride at 1 loo, the heating being continued for several hours. The excess of trichloracetyl chloride was distilled off under diminished pressure, and a fraction (30 grams) passing over at 185-204'was repeatedIyfractionated,when 9 grams of the rnethylic salt distilling a t 199--200°, under about 15 mm.pressure, and with the oil-bath at 225', mere obtained. The chlorine in this was determined.GROUPS ON THE ROTATORY POWER OF GLYCERATES, ETC. 185 1. 0.7007 gave 1.4557 AgC1. 2. 0.6275 ,, 1.3087 AgCl. C!=51*59 ,, C1= 51.40 per cent. C,HGO,C1, requires C1= 5 1 a82 per cent. The rotation was determined at the following temperatures. liotation of Methylic Di-ti.ichloi.acety~~Z~cer~tte. Observed rotation Density compared T ~ X U ~ J . in 44 i i m ~ tube. with water at 4". [.ID [ 6 1 D 11.5" - 10*03O 1.6125 - 14-13' - 144.5" 98.3 - 10.07 1.4964 - 15-29 - 148.8 1 2 - 10.05 1.6118 - 14.1i - 144% The density determinations actually made were cl 1 17"/4' = 1 *6 122. d 50"/4O = 1.5582. d 100"/4" = 1.49112. 3thyZic ~~o?zo-ts.iciLZorncety~tai,trccte. --Thirty grams of ethylic tartrat u (aD = + 8-47", t = 13', I = 1) and 200 grams of trichloracetyl chloride, heated a t 120" for 3 hours as before, were subsequently distilled under diminished pressure ; the excess of trichloracetyl chloride passed over first ; a t 160°, what appeared to be unaltered ethylic tartrate wab collected, whilst the ethylic salt (40 grams) came over mostly at 190".After two refractionations, the boiling point was 195' (oil bath 230°, pressure about 16 mm.), and as the rotation had hardly been affected by the last distillation, the chlorine mas determined by Carius' method. 1. 0.5463 gave 0.6625 AgC1. C1= 30.00 per cent. 2. 0.5486 ,, 0.6635 AgC1. C1=29.92 ,, The substance was then again twice redistilled, the boiling point being 185' (oil bath 210", pressure about 16 mm.), and the final pro- duct again analysed.1. 0.5804 gave 0.7050 AgC1. C1= 30.05 per cent. 2. 0.6782 ,, 0.8220 AgCl. C1=29*98 ,, C,,K,,07CI, requires C1= 30.30 per cent. C,,H,,08Cl, ,, 01=42*48 ,, The -substance obtained was, therefore, ethylic mono-trichloracetyl- With this, the following polarimetric observations were made. tartrate.186 FRANKLAND AND PATTERSON : EFFECT OF THE CHLORACETYL Rotcction of Ethylic Mono-tric~loracetyltar2~~ute. Obsorved rotation Temp. in 44 mm. tube. 11 *6O + 9.37" 98.5 + 10.01 58-2 + 9.88 46.2 + 9-81 38.5 + 9.77 12.0 + 9.39 Density compared with water at 4". [ a ] , 161, 1.3963 + 15.25" + 134.5' 1.2981 + 17.53 + 147.2 1 *3446 + 16.70 + 143-6 1.3609 + 16.39 + 142.0 1.3744 + 16.16 + 140.9 1,3959 + 15-30 + 134.8 The density determinations actually made were Methylic Mono-trichZos.cccet~/Itartrc~€~. -Thirty grams of methylic tar- trate (aD = + 2-28', t = 16', E = l ) , and 150 grams of trichloracetyl chlor- ide, after heating a t 110" for two days, on distillation as before, pave st fraction at 180-210" which crystdlised soon after cooling.The crystals, after treatment with water to remove any unaltered rnethylic tartrate, were pressed between filter paper and dissolved in toluene. This solution, after drying with calcium chloride, was allowed t o crystallise, and the greater part of the substance remaining in solu- tion was deposited on adding light petroleum : 21 grams of crystalline substance were obtained. On recrystallisation from xyleue, the melting point was 'i9-80°,-and two Carius' determinations of the chlorine gave the following results.1. 0,4737 gave 0.6286 AgC1. 3. 0.5293 ,, 0.7015 AgC1. Cl=32*77 ,, d 11'/4' = 1 *3970. d 50'/4'= 1.3541. d 100'/4' = 1.2964. C1=32.83 per cent. C,H,O,UI, requires C1= 32.92 per cent. The substance obtained was, therefore, methylic mono-trichloracetyl- tartrate. The crystals of which the above analyses were made were recrystal- lised from hot xylene; after washing with a little xyleue, they were ground up, and the powder, washed several times by decantation with light petroleum, was collected and dried in a vacuum desiccator. Its melting point was found as before to be 79-80', and with it the following polarimetric observatioiis were made. C,,H,O,Cl, ,, C1=45.42 ,, h'otatiou OJ Metlylic ?I.iol~o-tricl~Zo~~cccetyltar~~ccte. Temp.in 44 mm. tube. with water at 4". c a 111 [SID 1 ooo + 6 ~ 2 9 ~ 1 -408 1 + 10.15* + 87.55' 62 + 5-92 1 a4536 + 9.25 + 81.53 51.5 + 6.77 1.466'i + 8.94 + 79.23 17 + 5.50 1.5083 + 8.29 + 74-82 Observed rotation Dciisity comparedGROUPS ON THE ROTATORY POWER OF QLYCERATES, ETC. 187 The density terminations actually made were d 17'14" = 1.5083. cl 50G/40 = 1.4696. d 1So/SG =1*5056. d 100°/40 = 1.4081. 11. D I c H LO RAC ETY L DERIVATIVES. Preparation of i)ichZoracetyl ChZoride.--This was prepared by passing dry hydrogen chloride over a heated mixture of 100 grams of dichlor- acetic acid and 150 grams of phosphoric anhydride. The action proceeds readily, the product being more rapidly obtained than in the case of the trichloracetyl compound ; there is, however, a considerable amount of charring and a quantity of gas, consisting almost exclusively of carbonic oxide, is given off.* Zthylic Di-dichIoracetylglyc~~c~te.-This was prepared in the usual way from 28 grams of ethylic glycerate (aD = - 11.40°, t = 23O, I = 1) and 200 grams of dichloracetyl chloride heated at 106" for two days, and then repeatedly fractionating.The crude product was washed with a warm solution of sodium carbonate, and extracted with benzene. The benzene solution was again washed with sodium carbonate, then several times with water, and after drying with calcium chloride, the beuzene was first distilled off under atmospheric pressure, the residue being distilled under diminished pressure. The final product (7 grams) thus obtained distilled at 203' (oil bath a t 250°, and under about 15 mm.pressure). The chlorine was determined by the Carius-Volhardt method. A good yield was obtained. (Walker and Henderson, Chem Netus, 71, 103, 205). 1. 0.2228 required 0.4236 AgNO,. C1= 39-71 per cent. 2. 0.1588 ,, 0.3011 AgNO,. C1=39.60 ,, C,H,,O,CI, requires (21 = 39.89 per cent. The following polarimetric observations were made. Observed rotation 'l'emp. in 44 inm. tube. 16.8" - 11.82" 35.1 - 12.17 46.5 - 12.31 59.7 - 12.41 99 - 12.66 16.8 -- 11 .ss Density con;l)ared with water at 4" [ a ] , 1.4667 - 18.32" 1.4446 - 19.15 1,4291 - 19-58 1.4129 -- 19.96 1.3669 - 21.05 1.4667 - 18.33 * The decoiupositioii may possibly be represented thus CHCI,*COOH = 2CO + 2HC1 CHCI,*COOH = CO, -I- C I- 2HC1 [&ID - 167.6" - 173.4 - 176.0 - 183.7 - 178.1 - 167.6 1 I I t,lii.; coiiiiectioii, i t Le meill ioiicd that Alauineni (A?>uZe/z, 1865, 133, 154) has show^ t h a t the silver salt, 011 I~cating, decoinposcs into cnlbonic oxide, carbonic anhydride, and silver chloride.188 FRANKLAND AND PATTERSON : EFFECT OF THE CHLBRACETYL The density determinations actually made were d 16*8"/4"= 1.4667.d 31*5'/4' = 1.4485. d 46*5"/4' = 1.4291. d 59.7"/4"= 1.4129. d 100°/4"= 1,3657. Metlqlic Di-dichIorcccet?/lgZycel.cLte.-FiEteen grams of methylic glycerate (a, = - 6*44O, t = 16*5', I = 1) and 170 grams of dichloracetyl chloride, heated a t 11OOfor three days, were distilled as before,and passed over chiefly (30 grams) at 200-210°. This distillate was shaken up with a warm solution of sodium carbonate and extracted with benzene, and the benzene solution was again washed with sodium carbonate solution and then with water ; after drying with calcium chloride, the benzene was distilled off under atmospheric pressure, and the residue under diminished pressure.On repeated fractionation, which did not appreciably affect the rotation, the final product passed over at 207" (oil bath 260°, 20 mm. pressure). The chlorine was determined by the Carius-Volhardt metbod. 1. 0.3515 required 0,6942 AgNO,. Cl= 41.24 per cent. 2. 0.3894 ,, 0.7672 AgNO,. Cl=41.14 ,, C,H,O,Cl, requires C1= 41.52 per cent. The following polarimetric observations were made. lZo t at ion of J l e thy ti c Di-d icldoi-ace t 9 1yZ y cei *a t e .Observed rotatioil Density compared Temp. in 44 min. tube. with water at 4". L a l o 100 - 10.76 1.4235 - 17.18 74.4 - 10.53 1.4553 - 16.44 55 - 10.32 1.4796 - 15*S5 40 - 10.05 1.4982 - 15.25 14.5 - 9-39 15" - 9.39" 15290 - - 13-96' La]" - 129.6" - 152.0 - 147.9 - 143.9 - 139.6 The density determinations actually made were d 20°/4" = 1.5228. d 40°/4" = 1.4982. t l 60"/4" = 1.4734. d 80"/4O= 1,4484. d 100°/4"= 1.4235. E'tlqlic Di-dicl~Zol.ucetyZtc~~~t~c~te.-Thirty grams of ethylic tartrate (aD = + 9*31°, t = ZOO, I = 1) and 180 grams of dichloracetyl chloride, heated a t 110" for three days, gave a product the chief portion of which, on fractionation, passed over at, 220-230" (oil bath 260°, 20 nini. pressure). This was shaken with a hot solution of sodium carbonate and ex- tracted with benzene, &c., as in the preparation of the corresponding The yield was 35 grams.GROUPS ON THE ROTATORY POWER OF GLTCERATES, ETC.189 glycerate (p.~.). The product, redistilled until the rotation was constant. boiled at 225' (oil bath 260°, about 15 mm. pressure). The chlorine was determined by the Carius-Volhardt method. 1. 0.1685 required 0.2648 AgNO,. C1= 32-88 per cent. 2. 0.1681 ,, 0,2625 AgNO,. C1=32.61 ,, C,,H,,O,Cl, requires C1= 33.18 per cent. The following polarimetric observations were made. Rot ci t i o n of Et h y lie D i-d ichlom ce t y E t ctr t 9 '(6 t e . Observed rotation Density compared Temp. in 92'35 mm. tube. with water a t 4". [.ID [ 6 1 D 16" + 81.28' 1.4137 + 16.30' + 154.7' 41.5 + 21.07 1,3845 + 16.48 + 154.2 54.7 + 20.92 1,3695 + 16.54 + 153.7 74 + 20.92 1.3468 + 16.82 + 154.5 l(J0 + 20.78 1.3171 + 17.08 + 154.7 The density determination's actually made were d 21°/4'= 1.4080.cl 40'/4' = 1.3862. d 60'/4' = 1.3635. d 80'/4' = 1.3397. d 100°/40= 1.3171, Methglic Di-dicl~lorucetgltartrccte. -T hirty grams of met hylic tartrate (a, = + 4.57, t = 16', E = 2) and 150 grams of dichloracetyl chloride, were heated a t 1 10' for two days, and the product fractionated as before ; the excess of acid chloride came over a t about 50', and the methylic salt between 170-220°, chiefly a t 180' (oil bath a t 215-250'). On refrac- tionating twice, some of the distillate crystallised spontaneously, and crystallisation was induced in the remainder by st,irring with water. The solid was purified by trituration with a solution of sodium carbonate, drying on porcelain, and recrystallisation from xylene, the crystals being washed with a little xylene and then with light petroleum.The melting point was 63.5-64'. A further quantity was recovered from the xylene solution by precipitation with light petroleum, the total amount being 8 grams. This was distilled, the boiling point being 220-221' (oil bath 260°, about 15 mm: pressure), and the distillate, which rapidly solidified, melted at 64-45', The chlorine was determined by the Carius-Volhardt method. 1. 0,2243 required 0.3801 AgNO,. 2. 0.2427 ,, 0.4117 AgNO,. C1=35~42 ,, C1= 35.39 per cent. CloH,oO,CI, requires C1= 35.50 per cent.. The following polarimetric observations were made.190 FRANKLAND AND PATTERSON : EFFECT OF THE CHrAORACETYT, Rotcction of Met?hglic Di-cEic~lo?.cccet2/Ztnl.tl.nte. Observed rotatioil Deiisity compared Temp.in 44 mm. tube. with water at 4". Call) [all) 19.2' + 7.93" 1.5056 + 11-97" + 115.9' 37-6 + 7.47 1.4827 + 11-45 + 109.7 48.2 + 7.26 1.4693 + 11.23 + 106.9 55.2 + 7-16 1 *46 065 + 11.14 + 105.7 98.5 + 6.80 1.4101 + 10.96 + 101.s The density determinations actually made were tl 19'/4O= 15058. d 54O/4"-7 1,4620. d 100°j40= 1.40853. 111. &/I: o NOCIILO RACET Y L D E R I v A T I VES. Preparuiion of Monochlorucetyl Chloride.-Considerably greater difi- culty was encountered in the preparation of this than in the case of either the di- or tri-chloracetyl chlorides, owing to the very large amount of charring which takes place when monochloracetic acid is heated with phosphoric I? nhy dride.The method ultimately adopted consisted in introducing into a Wurtz ff ask, of 2 litres capacity, 150 grams of phosphoric anhydride, followed by 100 grams of melted monochloracetic acid. The flask containing the mixture was then a t once heated in an oil bath t o about 200', a rapid current of dry hydrogen chloride being passed through. The prin- cipal source of danger is the choking up of the lateral tube by the charred mass, which has a tendency to become extremely voluminous. I n one experiment, 83 gmms of crude chloride were obtained from 100 grams of the acid. The chloride was fractionated by means of a Heinpel tube, and, after one distillation, was almost entirely free from phosphorus.We may mention that we avoided the ordinary methods of preparing monochloracetyl chloride, because, firstly, the chlorination of chloracetyl chloride might lead to the formation of some dichloracetyl chloride, and, secondly, the method of acting with the chlorides of phosphorus on monochloracetic acid yields a product containing phosphoriis com- pounds, which we were unable to remove by any available means. Instead of monochloracetyl chloride, we tried, however, the use of monochloracetyl bromide for acting on ethylic glycerate, but obtained a n ethereal salt containing some bromine, and this method mas, there- fore, abandoned. Etlhylic Di-~~zonoc?r,ZorucetyZgZ~ce~*~~e.-~eventeen grams of ethylic. glycernte (a, = - 11-49', t = 14*5O, I = 1) and 90 grams of monochlor- acetyl chloride mere heated a t 110' for two days.On fractionating, the principal product came over a t 200--205° (oil bath 235'. pressureGROUPS ON THE ROTATORY POWER OF GLYCERATES, ETC. 191 about 18 mm.); this was twice refractionated, the rotation being practically unaffected by the last distillation. The final product dis- tilled at 198' (oil bath 235O, pressure about 15 mm.). The chlorine was determined by the Carius-Volhardt method. 1. 0.1700 required 0,2058 AgNO,. C1= 25.28 per cent. 3. 0.5123 gave 0.5246 AgCl (gravim.). C1= 25.33 The following polarimetric observations were made. 2. 0,2034 ,, 0.2464 AgNO,. C1=25.29 ,, ,, C,H,,O,Cl, requires C1= 24.74 per cent. Rotation of Etlzylic Di-nzonoc~Zoi.cccet?/lglyce. Observed rotation Density compared Temp.in 44 min. tube. with water at 4". [ a ] , 161r) 100' - 12.34' 1.2704 - 22.08' - 170.8' 66 - 11.88 1.3089 - 20.52 -- 162.0 40 - 11.13 1.3402 - 18.87 . - 251.4 15 - 10.12 1.3693 - 16.80 - - 136.6 The density determinations actually made were d 16'/4'= 1.3681. (1 8Oo/4O= 1.2922. d 5Oo/6O = 1.3279. d 100°/4' = 1.2704. Methylic Di-~?~oizocl~loiwacetylglycerate.-The methylic glycerate used mas derived from 35 grams of crystallised calcium glycerate. The rotation of the methylic salt was aD = - 6*24', t = 14*5O, I = 1. This methylic glycerate was heated at 110' with 80-90 grams of monochloracetyl chloride for two days. On fractionating the mixture, 21 grams of product were obtained boiling at 190-205O (oil bath 230°, pressure about 15 mm.); this was successively washed with solution of sodium carbonate and with water, extracted with benzene, &c.(see p. 187). On fractionation, the main portion passed over at 197' (oil bath 235", pressure about 15 mrn.). This, when redistilled, exhibited the same boiling point and practically the same rotation. The chlorine was determined by the Carius-Volhardt method. 1. 0,2044 required 0.2570 AgNO,. 2. 0.5623 gave 0.5977 AgCl (gravim.). The following polarimetric observations were made. C1= 26.26. C1= 26.30. C,H,oO,C)l, requires C1= 26.01 per cent.192 FRANKTJANT) AND PATTERSON : EFFECT O F THE CHTJ~RACETYTJ Rotation of Metlq Zic Bi-monoclhy Zorncet$'gZ~cerccte. Observed rotation Density compared Temp. in 44 inm. tnbe. with water a t 4". r a1LI E61D 100' -10.49" 1.3251 - 17.99" - 140.8 40 - 9.04 1.3954 - 14-72 - 119.3 29.2 -8.68 1.4099 - 13.99 - 114.1 15 -- 8.10 1,4263 - 12-91 - 106.1 65 - 9.76 1.3662 - 16.24 - 129.7 The density determinations actually made were d 17"/4"=1*4240.d 40'/4"= 1.3954. d 60°/4"= 1.3722, d 80°/4'= 1.3480. d 100"/4"= 1.3251. This substance subsequently crystallised spontaneously, and tho solid melted at 43-44'. Ethylic Di-monochlomcetyltartrute.-A mixture of 15 grams of ethylic tartrate (aD= + 8-77", t = 16", I = 1) and 80 grams of monochloracetyl chloride was heated a t 110" for three days, and then fractionated as before until the rotation was constant. The boiling point of the final product was 217" (oil bath 245", pressure about 15 mm.). The chlorine mas determined by the Carius-Volhardt method. 1. 0.2073 required 0.2011 AgNO,.2. 0.5428 gave 0.4418 AgCl (gravim.). The following polarimetric observations were made. (71 = 20.25 per cent. C1= 20.13 per cent,. C,,H,,O,Cl, requires C1= 19.78 per cent. Motation of Ethylic Di-molzocl~loracet~~ta~trccle. Observed rotation Density compared Temp. in 44 mm. tnbe. with water a t 4". Caln E61 100" + 6.44' 1.2394 + 11.81" + 96-84' 74.5 + 5.89 1.2667 + 10.57 + 87.93 49.5 + 5.29 1,2935 + (1.29 + 78-42 41 + 5.11 1.3026 + 8.92 + 75.58 15.5 + 4.33 1.3306 + 7.40 + 63.59 The following were the density determinations actually made. d 1S0/4" = 1.3279. d 40°/4" = 1.3040. d 6Oo/4O = 1.2823. d 80°/4" = 1.2603. d 100'/4" = 1.2394. After the above results had been obtained, we became aware of the fact t h a t methylic, ethylic, propylic, and isobutylic di-monochloracetyl- tartrates had already been prepared by Freundler (Bull.soc. chim., 1895, [iii], 13, 1055-1063). The following figures are given by him for the ethylic compound. B. p. 195-197"(12 mm. pressure), densityat 15O= 1.311 [a];"= + 9.4".GROIJYS ON THX ROTATORY POWER OF GLYCERATES, EN. 193 The specific rotation is thus higher by 2' than that found by us for the same temperature, whilst the density and boiling point are slightly lower. In consequence of this discrepancy, the preparation of this com- pound has been repeated by one of us in conjunction with Dr. Turnbull, the results being recorded in the paper which follows this. Methylic Di-n,aonochZosacet?lZtartl.ute.-From 20 grams of methylic tartrate (a, = + 4*5'i0, t = 16', 1 = 2) and 130 grams of monochloracetyl chloride heated at 110" for 2 days, 30 grams of product were obtained, distilling between 220" and 235" (oil bath 260°, pressure about 15 mm.).This solidified when triturated with a solution of sodium carbonate, and, after drying on porcelain, was crystallised from toluene, the crystals washed with light petroleum and then distilled. The boiling point was 217' (oil bath 260°, pressure about 18 mm.), 15 grams of this purified product being obtained, The substance crystallises from toluene in large, truncated pyramids; the melting point was 55'. The chlorine was determined by the Carius-Volhardt method. 1 0,2047 required 0.8092 AgNO,. C1= 21.34 per cent. 3. 0.2013 ,, 0.2059 AgNO,. Cl=21*36 ,, Cl,Hl,08C1, requires C1= 21.45 per cent.The following polarimetric observations were made. Rotatioiz of XethyZic l).i-1,ionochlorclcetyltara.ate. Observed rotation 'i'eiup. in 44 mm. tube. 100" + 1 ~ 5 0 ~ 75.3 + 0.76 54.7 + 0-25 43.3 - 0.05 33.6 - 0.16 14 - 0.50 Density compared with water at 4". c a10 L-510 1,3264 + 2-57" + 21-46" 1.3547 + 1.27 +10.80 1.3784 + 0.41 + 3.53 1.3915 - 0.08 - 0.70 1.4026 - 0.26 - 2-25 1.4250 - 0.80 - 6.98 The following were the density determinations actually made. d 19'/4'= 1.4193. d 40'/4" = 1 *3953. d 60°/4' = 1.3722, d 80°,'40 = 1.3492. d 100"/4"== 1.3264. Methylic di-monochloracetyltartrate has also been prepared by Freundler (loc, cit.), who describes it as an extremely syrupy liquid distilling a t about 187--190' (14 mm. pressure) and of density 1.409 a t 18'.The rotatory power hegives as polarimetric results which are, therefore, even more at variance with ours than in the case of the corresponding etbylic compound reFerred VOL. LXXIII. 0194 FKANKLAND AND PATTERSON : EFFECT OF THE CHLORACETYL ho above. His density is distinctly, and his boiling point considerably, lower than ours. I n consequence of this marked discrepancy, the preparation of this substance has also been repeated with some modifications by one of us in conjunction with Dr. Turnbull, and the results are recorded in the paper which follows this. M. Freundler has determined also the molecular weights of the methylic and propylic salts of di-monochloracetyltartaric acid by the cryoscopic method, using benzene and ethylenic dibromide as solvents, and we may take the+ opportunity of pointing out that he gives throughout an erroneous theoretical value for the molecular weight of each of these ethereal salts.Thus for the methylic di-monochloracetyl- tartrate he makes all his calculations on the basis of the true mole- cular weight being 431 instead of 331, and in the case of the propylic compound he uses the molecular weight 487 instead of 387. In~~uenck ~f tlbe CMomcetpl GTOUPS 0% t?Ae PlqsiccbI Ps*opes.ties. 1. An examination of the results recorded in the preceding pages shows that the introduction of two monochloracetyl groups (a) Increases the lsevo-rotation of methylic and ethylic glycerate, the effect being very similar to, but slightly greater than, that produced by the introduction of two acetyl groups, thus Methylic glycerate ................................. [a]?=- 4.80" ,, diacetylglycerate ........................ [u]:"= - 12-04 ,, dimonochloracetylglycerate .........- 12'91 Ethylic glycerate ................................... [ a]i6"= - 9'18 dimonochloracetylglycerate ........... [ a ] r = - 16.80 ,, diacetylglycerate ........................ [ u ] ~ " = - 16.31 ), ( b ) Considerably reduces the dextro-rotation of methylic tartrate, and barely increases that of ethylic tartrate ; the effect on the latter is, in fact, hardly appreciable. I n this respect, the effect of the two monochloracetyl groups resembles, although it is far inferior to, that produced by the introduction of two acetyl groups. Thus two acetyl groups greatly reduce the dextro-rotation of methylic tartrate, and very considerably reduce that of ethylic tartrate, Rlethylic tartrate ........................... [a]?= + 2-14' (liquid), ,) diacetyltartrate ...............[a]:5n= - 15.1 (inabsolute alcoholic solution) ), di-moiiochloracetyltartrate.. , [a - 0'64 (liquid). Ethylic tartrate ........................... [a f 7 '66" di-monochloracetyltartrate ... [uEoo= i- 7-67" , , diacetyltartrate.. ................ t = 25", I = 1, a= + 5" ,, All three ethylic salts were examined in the liquid state.GROUPS ON THE ROTATORY POWER OF GLYCHRATES, ETC. 195 I n this respect, our results are in direct opposition t o those of M. Freundler, who finds that the introduction of the two mono- chloracetyl groups slightly but appreciably increases the dextro-rotation of both methylic and ethylic tartrates respectively.We would remark in this connection that we have obtained both the methylic and ethylic di-monochloracetyl tartrates in a crystalline state,"whilst M. Freundler has only handled them in the liquid condition. The diminution in the dextro-rotation of methylic and ethylic tartrate effected by the introduction of the two monochloracetyl groups is much more conspicuous if the rotations at a high temperature are taken into consideration, thus Methylic tartrate ................................... [a];O"= + 5-99" di-monochlorace t y 1 tartrate ......... [.I;;" = + 2-57 , , Ethylic tartrate .................................... [ a]!'o'= + 13-29 ,, di-monochloracetyltartrate ............ [u]~~'= +11'81 2. Similarly, the above results show that the introduction of two dichloracetyl groups (a) Jncreases the laevo-rotation of both methylic and ethylic glycer- ate, the laevo-rotation of these di-dichloracetylglycerates being, how- ever, only slightly greater than the corresponding di-monochlor- acetylglycerates ; indeed, this relationship only holds good at low temperatures, for a t high temperatures the lzvo-rotation of the di- monochloracetylglycerates slightly but distinctly exceeds that of the corresponding di-dichloracetylglycerntes. Thus- [ a ] y [ a ] y Methylic glycerate ........................ - 4.80" - 8'31"t (calculated).,, diacetylglycerate ............... - 12'04 - 19 '24t (calculated). , , di-monochloracetylglycerate.. - 12'91 - 17 '99 ,, di-dichloracetylglycerate ......- 13'96 - 17'18 Ethylic glycerato ........................... - 9.18 - 12-55? (calculated). ,, diacetylglycerete ............... - 16'31 - 23'09t (calculated). , , di-dichloracetylglycerate ...... - 18'20 - 21.1 ,, di-monochloracetylglycernte.. . - 16 *80 - 22.08 * See the next paper. .t. I t should be pointed out that these values of [aID at 100" have been calciilated for methylic and ethylic glycerates and diacetylglycerates from the materials given in the papers by P. Frankland and MacGregor (Trans., 1893, 63, 1415 ; Trans,, 1894, 65, 754 ; Trans., 1894, 65, 768). 'l'hese materials enable the observed rotation, aD, to be extrapolated for loo", whilst the density for looo has been cal- culated by means of the average decrement in density, 0*0012211, for la rise in temperature, this average decrement having been obtained from density observations made on ethylic mono-trichloracetyltnrtrate, methylic di-dichlor:icctyltnl.tl.rrtc, tehylic di-dichlornceltylgycerate, and nietliylic di-trichloracetylglycerate.0 2196 PRANKLANI) hN1) lJATTEKSON : EFFECT OF THE CHLORACETYL ( b ) Very greatly increases the dextro-rotation of both methylic and ethylic tartrate, thus :- [ a]:O" Methylic tartrate ..................... + 2.14" , , di-dichloracctyltartratc + 11 '9 Ethylic tartrate ........................ + 7.66 , , di-dichloracetyltartrate ... + 16 *3 The rotation of these di-dichloracetyltartrates is. comparatively insensitive to temperature, the dextro-rotation of the et hylic compound increasing but slightly with rise of temperature, whilst that of the methglic compound very slightly declines under the same circum- Ytances.But even if the rotations a t 100" be compared, the introduc- tion of the two dichloracetyl groups effects a large increase in the dextro-rotation of both methylic and ethylic tartrate. Thus [~l;;uO Methylic tartrate .................... t 5.99" ,, cli-dichloracetyltartrate + 10.0 Ethylic tartrate ........................ + 13'29 ,, di-dichloracetyltartrate ... + 17'08 The effect on the dextro-rotation of methylic and ethylic tartrate produced by the introduction of the two dichloracetyl groups resembles that produced by the introduction of two phenacetyl groups, Thus Methylic di-phenacetyltartmte ...... + 14.5" (Freundler), Ethylic ...... [a];""= '15.3 ,, ,, 3.The introduction of two trichloracetyl groups was only found possible in the case of the glycerates, both methylic and ethylic tartrates yielding only monacidyl derivatives, The introduction of the two trichloracetyl groups has the effect of (a;) increasing the laevo-rotation of the methylic glycerate to a greater extent than the introduction of two dichloracetyl groups. This is, however, only the case at low temperatures, for the rotation of methylic di-trichloracetylglycerate, being but very slightly increased by rise of temperature, the laevo-rotation of methylic di-dichloracetyl- glycerate at 100" is markedly greater than that of methylic di-trichlor- acetylglycerate at this temperature. Thus at 100' the laevo-rotation of methylic glycerate is most increased by the introduction of the two monochloracetyl groups, and least by that of the two trichloracetyl groups.The relative effects on the laevo-rotation of ethylic glycerate pro- duced by the introduction of these several groups is exactly similar, The rotation of ethylic di-trichloracetylglycerate is almost perfectlyGROUPS ON THE ROTATORY POWER O F GLYCERATES, ETC. 197 insensitive to temperature, but, if anything, rise of temperature causes diminution in lavo-rotation. [a1;50 [ u ~ y Methylic glycerate ..................... - 4.80" - 8-31"' (calculated). ), diacetylglycerate ............ - 12.04 - 19-24" (calculated). ,, di-monochloracetylglycerate - 12-91 - 17.99 ,, cli-dichloracetylglycerate ... - 13.96 - 17-18 ), di-trichlorncetylglycerate - 14.2 - 15.3 Ethylic glycerate ........................- 9-18 - 12.55" (calculated). ,, diacetglglycerate ............ - 16'31 - 23.09" (calcnlated). , , di-monochloracetylglycer~te - 16.80 - 22'05 ,, di-dichloracetylglycerate ... - 18 -20 - 21 '1 ), di-trichloracetylglycerate . - 18.7 - 18'4 It is interesting t6 compare with the above the rotation of the diphenacetylglycerates, of which only the methylic compound has been prepared by one of us (Trans., 1896, 69, 111). Nethylic diphenacetylglycerate [a31D5'= - 16'0" 9 , 9 9 [ u ] ~ " " ~ = - 13.4 From these figures it will be seen that, in rotatory effect, the phen- scetyl group differs even slightly more from the ncetyl group than does the trichloracetyl group. 4. The introduction of a single trichloracetyl gronp into methylic and ethylic tartrate respectively produces a change in their rotation very similar to that which is effected by the introduction of two dichloracetyl groups into these same compounds, thus [a]$" [ a];oop Methylic tartrate ................................ + 2'14" -t 5 *99" ,, mono-trichloracetyltartratc......... + 8.4 + 10.15 ,, di-dichloracetyltartrate'. .............. + 16'3 + 17'08 In this connection, it is worthy of note that the introduction of n single monochloracetyl group? produces an effect closely resembling that which attends the introduction of the trichlorncetyl group, thus , , di-dichloracetyltartrate ............ + 11 -9 -i- 10'9 Ethylic tartrate.,. ............................... + 7 *6G + 13'29 ,, inono-trichloracetyItartrate .........+ 15.5 -i- 17.6 [a]:')" [ a]:wp"" EthyIic mono-monochlorncetyltnrtrate (slightly impure) -k 11 *44" + 17'32" and, as so frequently pointed out above, any preponderating influence of the di- and tri-chloracetyl groups as compared with that of the monochloracetyl group tends to become equalised at a high temperature. 5. The influence which the several groups under consideration in this paper exercise on the molecular deviation ([S],) may be suinmarised in the following tabular statements. * The footnote on p. 195 applies also here. 1. See 1'. 204, i n nest paper,198 MONO-, nr-, AND TRI-CHLORACE'I'YL GROUPS, ETC. I6 Differences Methylic glycerate .......................... .., diacetylglycwate ............... ,, di-monochloracetylglycerate ... , , di-dichloracetylglycerate ......,, di-trichloracetylglycerate ...... - 145 1 Ethylic glycerate ........................... - 52.8" ,, diacetylglycerate .................. - 108'2 I '':" } 84.2 113.2 ,, di-monochloracetylglycerate ... - 137 28 } 1134.2 29 ,, di-dichloracetylglycerate ...... - 166 ,, di-trichloracetylglycerate ...... - 187 } 21 [ 6 1150 Differences Methylic tartrate .............................. + 13" , , diacetyltartrate .................. , , di-monochloracetyltartrate ... ,, di-dichloracetyltartrate ......... , , niono-trichloracetyltartrate ... + 73 } - 43 ,, di-monochloracetyltartrate ...... i- 63 1 - ,, di-dichloracetyltartrate ........... + 155 1 +92 ,, mono-trichloracetyltartrate ...... -t 135 } -20 .............................. , , diacetyltartrate ..................... unknown + 4 9 0 ~ - Ethylic tartrate The relationship between the rotations of the several compounds we have investigated, and the influence of temperature on the rotation of each, is best shown by means of the diagrams, pp. 199, 201. From the diagram p. 201, it will be seen (a) That the specific rotations of methylic di-monochloracetyl- glycerate and methylic di-dichloracetylglpcerate are identical at 62", the rotations of the corresponding e t hylic compounds becoming iden- tical at 53". ( 6 ) That tbe methylic di-dichloracetyIglycerate and di-trichloracetyl- glycerate have an identical specific rotation at 21", the corresponding ethylic salts having also an identical specific rotation a t 2 2 O . (c) That the specific rotations of the methylic di-trichloracetyl- glycerate and di-monochloracetylglycerate become equal at 379 the rotations of the corresponding ethylic compounds, becoming equal 8.t almost exactly the same temperature, namely, at 35". Thus it would appear that the influences which lead to an equal degree of asymmetry, in the case of the two methylic salts, are condi- tioned by the same, or nearly the same, temperature as conditions an equal degree of asymmetry in the case of the two ethylic compounds, MASON UNIVEKSITP COLLEGE, BIRMINQHAM.199 InJuence of Tenapemture 012 the Moleculcw Deviation of the Compounds FRANKLAND AND PATTERSON. 3- 15 + 10 + 5 - 51 .- l o ( described. 10' 20" 30" 40" 50" 60" 70" 80" 90" 16 Temperature.199 InJuence of Tenapemture 012 the Moleculcw Deviation of the Compounds FRANKLAND AND PATTERSON. 3- 15 + 10 + 5 - 51 .- l o ( described. 10' 20" 30" 40" 50" 60" 70" 80" 90" 16 Temperature.201 FRANKLAND AND PATTEMON. In@uence of Tempemturs on the Xpc;fic Rotcction q? the Compounds + 15 -t- 10 + 5 ye 0 Y s 2 -* u la 5 $i - 5 - 10 - 15 - 20 10' 20' 30" 40' 50" 60' 70' 80" 90' 100' Z'emperrature.

ISSN:0368-1645    

DOI:10.1039/CT8987300181

出版商:RSC    

年代:1898

数据来源: RSC

摘要:

INVESTIGATION OF INDIAN AND AMERICAN PODOPHYLLUM. 209 X V.-A Chemical Investigation of the Constituents of Indian and American Podophyllum (Podophyllum emodi and Podophyllum peltaturn). By WYNDHAM R. DUNSTAN, F.R.S., and T. A. HENRY, Salters’ Research Fellow in the Laboratories of the Imperial Institute. Podophyllum emodi is a small, herbaceous plant which grows abundantly in Northern India; it is figured and briefly described in Royle’s Ihhstrated Botang of the Himalayas. The root, or, more strictly, the rhizome, has long been used in Indian medicinal practice for the same purpose as that for which the allied American plant, Podophyllum peltatum, is employed in Europe and America, It acts as a powerful purgative, and, in particular, beneficially affects the liver. It has been frequently suggested that the constituents of both rhizomes are very similar, but they have never been completely examined (Watt’s Dictionary of the Economic Pvoduct:, of Incliu, 6, Part I.; Dymock, Imperial Institute Handboob of Commemial Products, No. 3 ; Umney, Pharnz. Journal, [iii], 12, 217 ; Thompson, Amer. Journ. Pharm., The chemical constituents of the rhizome of the AmericanPodophylZum pltatum have, however, been made the subject of several investigations, First, in 1832, Hodgson prepared the mixture of resins known and largely used in medicine as ‘‘ podophyllin,” by precipitating a concen- trated alcoholic extract of the rhizome with water ; this is now manu- factured on a large scale, and is the form in which ‘ podophyllum ’ is usually administered as a drug.The first important contribution to the chemistry of podophyllum was that made by Podwyssotski (Phamn. Journ., [iii], 12, 317, 1011); this chemist showed that the rhizome did not, as was previously supposed, contain the alkaloid berberine; he isolated from it three substances which he named podophyllotoxin, podophyllic acid, and podophylloquercetin respectively. To the first of these he attributed the characteristic purgative action of the drug, but the others he believed to be physiologically inert ; the first two he did not succeed in obtaining in a crystalline condition, the third was a crystalline, yellow colouring matter. He further showed that when podophyllotoxin is acted on by a1 kaline solutions, it is decomposed, furnishing two new substance8, one crystallising in long needles with a silky lustre, which he named picropodophyllin, and the other a gelatinous substance having the characters of an acid, which he called picropodophyllic acid.Kursten (Arch. Phurm., 1891, 228, 220-248), who considerably VOL. LXXIIT. P 189 1).210 DUNSTAN AND HENRY: A CHEMICAL INVESTIGATION OF THE amplified the work of Podwyssotski, succeeded in crystallising podo- phyllotoxin, and ascribed to it the composition represented by the formula C,,H2,0g,2H,0. H e showed also that by the action of alkalis it is converted into an isomeride picropodophy llin, and concluded that the picropodophyllic acid of Podwyssotski simultaneously produced is an oxidation product which can be prepared by the action of permanganate in alkaline solution.H e expressed its composition by the formula C,,H240g and called it podophyllic acid. H e obtained this acid crys- talline, and ascertained its molecular weight through the analysis of its copper s a l t ; he also determined that both picropodophyllin and podophyllotoxin have the same composition, and contain three methoxyl groups. The composition of Podwyssotski’s podophylloqueroetin lie represented by the formula C23H16010, and prepared crystalline hex- acetyl and hexabenzoyl derivatives from it ; from a n examination of these derivatives, and of the methyl ether of the colouring matter, he came t o the conclusion that podophylloquercetin and quercetin (from quercitron bark) are not identical. Very little has so far been done in the chemistry of PodophyZZurn emodi.The amount of resin in the rhizome has been estimated by Dymock and Hooper (Pharmacographia Indicu), and also by J. C. Umney (Pharm. Journ., [hi], 23, 207), who showed that i t contains Podwyssotski’s amorphous podophyllotoxin, but in smaller quantity than the American rhizome. The objects of the present investigation were to decide whether or not the constituents of the American and Indian plants are identical, to determine their constitutions as far as possible, and to ascertain whether the rhizome of the latter plant could be used as a source of the medicinal resin ‘ podophyllin.’ I n addition to the chemical ex- amination, physiological and therapeutical investigations of the action of the several constituents have been instituted, and the results of these will be separately published.Briefly stated, the principal results we have obtained are as follows, We have proved that the constituents of P. emodi are identical with those of P. peltaturn. Crystalline podophyllotoxin is shown to have the composition represented by the formula C1,Hl,O6,2H,O ; when acted on by aqueous alkalis it is converted into the isomeric picro- podophyllin; the gelatinous acid first producsd in this reaction is the acid corresponding to the lactone picropodophyllin, and not a n oxidation product, as Kursten supposed. It is also shown that both podophyllotoxin and picropodophyllin contain two methoxyl groups, that both furnish monobromo-derivatives, and, when fused with potash, yield orcinol and acetic acid, also that both furnish dimethyl- naphthalene when distilled with zinc dust.The formula C15H,406 is assigned to podophyllo toxin and picropodophyllin, and Cl5Hl6Of toCONSTITUENTS OF INDIAN AND AMERICAN PODOPHYLLUM. 211 podophyllic acid, and structural formuls are suggested for these substances, exhibiting them as derivatives of a substituted phenylated hydro-y-pyrone. The yellow colouring matter has been completely purified,lanalysed, and shown to have the composition represented by the formula C,,H,,07 ; it yields a pentacetyl derivative melting at 1 9 2 O , a tetramethyl ether (m. p. 1 5 6 O ) , and a compound with sulphuric acid corresponding exactly with the quercetin compound. When fused with potash, it yields phloroglucinol and protocatechuic acid. From this experimental evidence it is concluded that the colouring matter is identical with the quercetin of quercitron bark, and that, therefore, the use of the name podophylloquercetin is unnecessary.The removal of podophyllotoxin and podophylloquercetin from ‘ podo- phyllin ’ left a dark coloured, resinous powder, which was still physio- logically active ; attempts were therefore made to isolate this active substance from the residue. By treating it with absolute alcohol, followed by fractionttl precipitation of the solution with water, a viscid, brown resin was obtained, which proved to be active as a purgative; all attempts to crystallise this viscid resin were unsuccessful. I n the purest form in which we have obtained it, it is a transparent, reddish-brown substance, softening and becoming semi-liquid a few degrees above the atmospheric temperature.It yields a crystalline acetyl derivative, and from this we have ascertained indirectly that the podophyllo-resin probably has the formula C12H120,. We are indebted to Dr. H. W. G. Mackenzie, assistant physician to St. Thomas’s Hospital, aad Mr. W. Dixon, M.B., Salters’ Research Fellow in Pharmacology a t St. Thomas’s Hospital, for having examined the therapeutic effects and the physiological action of the constituents we have obtained from Podophyllurn emodi. An account of their work will be published in a separate form, and only the general conclusions will be indicated here. Therapeutic trial has proved that the podo- phylliu prepared from Podophyllum emodi is as valuable a purgative as the podophyllin obtained from P.peltaturn. The action of this resinous mixture is due partly to the podophyllotoxin i t contains, and partly to the active podophyllo-resin ’ mentioned above. Owing to its intensely irritating action internally, even when given in small doses, podophyllotoxin is unsuitable as a medicinal substitute for podo- pbyllin, whilst podophyllo-resin would seem to present no therapeutic advantage as compared with the podophyllin now employed. Picro- podophyllin, picropodophyllic acid, and the quercetin are very slightly, if a t all, active as purgatives. Since P. emodi furnishes more podophyllin than P. peltaturn, the Indian plant is of greater value as the source of this resin. Appended to this paper are results of determinations of the amount of resin con- tained in the rhizomes of plants collected in different districts of the P 2212 DUNSTAN AND QENRY : A CITEMICAL INVESTIGATION OB THE Punjab under the supervision of Dr.George Watt, C.I.E., Reporter on Economic Products t o the Government of India. Podophyllotoxin. Podwyssotski had shown that podophyllotoxin is precipitated when a chloroform extract of the rhizome of P. peltaturn is added to a large excess of light petroleum, and Kursten had found that by fractionally precipitating a chloroform solution of this crude podophyllotoxin a crystalline substance (podophyllotoxin) could be obtained. The method we finally adopted, after many trials, consisted in ,preparing the mixture of resins (podophyl1in)Ifrom the rhizome of P. emodi and then percolating this, in a Soxhlet extractor, with chloroform ; the chloro- form was distilled from the percolate, the dark brown extract boiled with benzene, and the hot benzene solution filtered into a cold flask and allowed to cool somewhat ; by this means, a good deal of resin was easily removed.The solution was then poured from the deposited resin, boiled for some time with animal charcoal, filtered, and set aside for several days, when almost colourless crystals of podophyllotoxin were obtained. These were purified by recrystallisation either from a mixture of chloroform and petroleum, or from alcohol and water. The pure substance, which forms colourless needles melting at 117", is easily soluble in alcohol, acetone, chloroform, and hot benzene, but only slightly in water.Its taste is very bitter. Analysis of a carefully purified specimen, which had been dried at 110' until no further loss of water occurred, gave the following results. 0,1121 gave 0,2534 00, and 0.614 H,O. C = 61.65 ; H = 5.09. 0.142 ,, 0.3246 CO, ,, 0.611 H,O. C = 62.24 ; H = 4.78. 0.1328 ,, 0.3025 CO, ,, 0,0667 H,O. C= 62.13 ; H=5*57. Mean C = 62.00; H = 5.11. C15H1406 requires C = 62.06; H = 4.82 p. c. We therefore adopt this formula as simpler than that suggested by Kursten, C,,H,40,,2H,0. Specijc Rotation of Podophyllotoxin.-For the determination of this constant, an alcoholic solution containing 2.417 grams in 100 C.C. of absolute alcohol was used in a 2-decimetre tube with Laurent's half- shade polarimeter. The compound is tstrongly ltworotatory. The mean of ten readings was - 4" 35'.Hence the specific rotation [ .ID is loo 40 35' = - 94" 48'. 2 x 2.417 Water of Crystallisation.-When podophyllotoxin is crystallised from A determi- a mixture of alcohol and water, i t separates as a hydrate. nation of the water gave the following result.CONSTITUENTS OF INDIAN AND AMERICAN PODOPHYLLUM. 213 0,2988 dried at 100' for 2 hours lost 0.0302; further dried at 110' until the weight was constant, it lost 0.0013; no further loss occurred a t 120O. 0.2988 therefore contains 0-0315 = 10.5 per cent. C,,H,,O6,2H,O requires Z 1.2 per cent. of water of crystallisation. Anhydrous PodophyZZotoxin.-The dried podophyllotoxin obt,ained in the previous experiment was dissolved in absolute alcohol, and the solvent then removed by exposure in a vacuous desiccator.As the solution became concentrated, crystals of anhydrous podophyllotoxin melting at 157" were obtained ; these pass into the ordinary hydrated substance when recrystallised from alcohol by adding wat,er. It was afterwards found that a very convenient method of obtaining anhydrous podophyllotoxin consists in heating the hydrated substance a t its melting point (1 17") for a few minutes, dissolving the product in dry chloroform, and adding dry light petroleum until the mixture is slightly turbid ; after standing a few hours, the anhydrous substance crystallises out. On exposure to air and light for several weeks, anhydrous podophy llotoxin acquires a purple colour ; the hydrated substance, on the contrary, appears to be quite stable under these conditions.The specific rotation of an alcoholic solution of anhydrous podophyllotoxin was found to be [ = - 78" 4'. Picropodoph y ZZin. If podophyllotoxin is boiled with aqueous alkalis until com- pletely dissolved, and the liquid is then acidified with dilute mineral acids, a white precipitate is thrown down; this is soluble in hot alcohol, and on cooling is deposited in the form of silky masses of long needles, melting a t 227". It has all the properties of Podwyssotski's picropodophyllin. It was found to be soluble in chloroform, acetone, and hot alcohol, and nearly insoluble in cold alcohol and water. Like podophyllotoxin, it has an extremely bitter taste, but has no rotatory action on polarised light. Analysis of a carefully purified specimen gave the following results.0.0895 gave 0.203 CO, and 0.0436 H,O. C = 61.86 ; H = 5.42. 0.1253 ,, 0.2841 CO, ,, 0.0604 H,O. C = 61.74 ; H = 5.35. MeanC = 61.8; H= 5.38. C,,H,,O,requiresC= 62-06; H = 4.82percent. Picropodoph yllin, theref ore, appears to be isomeric with podophyllo- toxin. As further proof of the isomerism of podophyllotoxin and picro- podophyllin, it should be added that when podophyllotoxin is heated in sealed tubes with water or dilute hydrochloric acid, some picropodophyl- lin is formed, and although decomposition products, such as methylic alcohol, &c., have been caref idly searched for, none have been found. The difference of even a methyl group makes a considerable difference214 DUNSTAN AND HENRY : A CHEMICAL INVESTIGATION OF THE in the percentage composition of this molecule ; thus, supposing picro- podophyllin to be rnethylpodophyllotoxin, C,,Hl3O,*CH,, this formula would require C = 63.15 ; H = 5.2 per cent.The results of the combustion of picropodophyllin recorded above cannot be reconciled with this, and the presence of an extra methoxyl or acetyl group would make the difference greater still. On the other hand, the combustions of podophyllotoxin are uniformly slightly lower in carbon than those of picropodophyllin. Podophyllotoxin . . . 6 1 *64 6 1.53 6 1 -1 3 6 1.5 1 6 1 -40 mean 6 1.4 Picropodophyllin. .. 61.86 61.74 61.93 ,, 61.8 But we believe that this is explained by the difficulty of obtaining podophyllotoxin completely anhydrous. The ’facts recorded subse- quently greatly strengthen the supposition that the two compounds are isomeric.From the experiments we have made, it does not appear that picro- podophyllin is an actual constituent of the plant. Po dophg 1 I ic A cid. I f the solution obtained by boiling podophyllotoxin with alkali is carefully cooled and then acidified by adding dilute acetic acid, no pre- cipitation occurs, but on standing for several hours (unless the solution is very concentrated) the whole solidifies to a transparent jelly. If this jelly is dissolved in alcohol and the solution allowed to stand, almost the whole of the podophyllotoxin originally used is obtained in the form of picropodophyllin. It is therefore evident that a very close connection exists between picropodophyllin and the gelatinous acid, which is probably the principal constituent of Podmyssotski’s picro- podophyllic acid, and Kursten’s podophyllic acid.We propose to retain for i t the name of podophyllic m i d . If picropodophyllin itself is boiled with alkalis it dissolves, and if this solution is cooled and acidified with acetic acid, it also gelatinises. All attempts to isolate this gelatinous substance failed ; when dis- solved, it invariably gives only picropodophyllin on removing the sol- vent, and when exposed in the vacuous desiccator, it leaves only a mass of crystals of picropodophyllin. It is apparently an acid, since it redis- solves on the addition of alkaline solutions, but as it does not react with any of the ordinary indicators, it is difficult to prepare salts by direct neutralisation.It was found possible, however, to prepare crystalline salts by the following method. Picropodophyllin or podo- phyllotoxin is dissolved in hot alcohol, and a sufficient quantity of alcoholic soda added to this solution, the mixture is then boiled for some time, and when crystals begin to form the mixture is allowed to cool, and the crystalline precipitate filtered off, washed once or twiceCONSTITUENTS O F INDIAN AND AMERICAN PODOPHYLLUM. 215 with alcohol and ether, and dried. It can be recrystallised from water or alcohol. S n aqueous solution of this substance gelatinises when acidified with acetic acid, and from this gelatinous material picropodophyllin is obtained by dissolving it in hot alcohol, and the substance when heated in a dry test tube yields a residue of sodium carbonate; the substance must therefore be the sodium salt of podophyllic acid.From this crystalline sodium salt, a silvey salt was prepared by double decomposition. Silver podophyllate is somewhat soluble in water, and is very unstable, becoming dark grey in a few minutes when exposed to light. Analysis of two specimens gave the following results. 0.0745 gave 0.0195 Age Ag. = 26-17 M~~~ = 25-69 per cent. 0.0706 ,, 0.0178 Ag. Ag. = 25.21 } C,,H,,O,*COOAg requires Ag = 25-82 per cent. The copper salt was prepared by adding solution of copper acetate to a solution of sodium podophyllate and slowly removing the water by evaporation in a desiccator ; it is thus easily obtained in light green prisms. When boiled with alcohol or water, the copper salt decom- poses, giving copper oxide, picropodophyllin crystallising from the alcoholic solution ; this decomposition was made use of for the determi- nation of the amount of copper contained in the salt. 0.1030 gave 0.0128 CuO= 19-42 per cent.(C,,H,,O,),Cu requires Cu = 11 08 per cent. The aqueous solution of sodium podophyllate is lsvorotatory ; a determination of the specific rotation, using a solution containing 2.7365 grams in 100 C.C. of solution in a 2-decimetre tube with Laurent's half-shade polarimeter, gave as the mean of ten readings 4.O 33'. Hence the specific rotation 100 x 4 O 33' [a],= --2.7365 = - 83' El'. From the experimental facts mentioned, it is clear that picropodo- These facts may (1) Picropodophyllin, when boiled with alkali, gives podophyllic acid.(2) Podophyllic acid loses water and becomes picropodophyllin. (3) The copper salt of podophyllic acid is decomposed on boiling with alcohol into cupric oxide and picropodophyllin, water being elimi- nated ; picropodophyllin must therefore contain the group -CO*O-. It was thought that possibly the gelatinous acid produced from podophyllotoxin might be an optical isomeride of that obtained from phyllin must be the anhydride of podophyllic acid. be summarised thus.216 DUNSTAN AND HENRY: A CHEMIICAL INVESTIGATION OF THE picropodophyllin, but the determination of the specific rot,ation of the former shows that the two are identical; this determination was carried out under the conditions mentioned above, using a solution containing 1.26’7 grams in 100 C.C.The mean of ten readings was - 2” 7’. Specific rotation [a]., = - 83” 31’. From these observations, we conclude that Podwyssotski’s picro- podophyllic acid, is not, as Kursten supposes, an oxidation product of podophyllotoxin having the formula C20H2409, but when pure is a monobasic acid of the formula C,,H,,07, of which picropodophyllin (CI,H,,O,) is the anhydride or lactone. Bat e m inat ion of Me thoxy I in Podoptiy lZotoxin and Picropodoph y ZZin. This estimation was carried out by Zeisel’s method; two experi- ments gave the following results. 0~203podophyllotoxin gave 0.3159 AgT. CH,O = 20.61. 0.1226 9 ) ,, 0,1918 AgI. CH,O = 20.71. C,3H,0,(OCH,)2 requires CH,O = 2 1.2 per cent. The determination of methoxyl groups in picropodophyllin gave the following results.0.2068 picropodophyllin gave 0.3346 AgI. CH,O = 21.43. 0.1 34 99 ,, 0,2204 AgI. CH30= 21.7. CI,H,0,(OCH3), requires CH,O = 2 1 *2 per cent. Podophyllotoxin and picropodophyllin, therefore, both contain two methoxyl groups. Action of Fused Potash on Podophyllotoxin. Guareschi (Ber., 1879, 12, 683) has examined the action of fused potash on ‘‘podophyllin,” which he recognises to be a mixture, and found that paroxybenzoic acid, pyrocatechol and protocatechuic acids were the principal products. When podophyllotoxin is added to melted potash and the mixture kept just fused for about half an hour, a dark brown “ melt ”is formed, This was dissolved in water, dilute sulphuric acid added in excess, the precipitate dissolved in ether, and after the ethereal solution had been decolorised with animal charcoal, the solvent was removed by distilla- tion, and the residue dissolved in boiling water, and precipitated with a solution of basic lead acetate.This precipitate was decomposed with dilute sulphuric acid, the mixture shaken with ether, the ethereal solu- tion dried over fused calcium chloride, and light petroleum added untilCONSTITUENTS OF INDIAN AND AMEliICAN PODOPHYLLUM. 217 the mixture was just turbid. At first a resinous substance was de- posited, but the later fractions consisted of a substance crystallising in colourless needles, and melting, after having been dried in the desiccator for some days, a t 107". It gave a violet coloration with ferric chloride solution. It had, therefore, the properties of orcinol, but the quantity obtained was insufficient for analysis.The solution of the melt, which had been acidified with dilute sul- phuric acid, was distilled, and the distillate, after being exactly neutralised with soda, was concentrated. Silver nitrate was then added and the white, crystalline precipitate collected, dried, and analysed. 0.0892 silver salt gave 0,0573 Ag. Silver acetate requires Ag=64*GI per cent. Ag= 64.2. The volatile acid is therefore acetic mid. No derivatives were obtained when podophyllotoxin or picro- podophyllin was allowed to react with acetic anhydride, benzoic chloride, or hydroxylamine ; in each case the substance was recovered unchanged. When solutions of podophyllotoxin and phenylhydrazine interact, a n oily precipitate forms on standing, but this could not be obtained in a crystalline condition, and has not been further examined.Action of Bromine on Podophyllotoxin. Finely powdered podophyllotoxin was made into a paste with glacial acetic acid, and bromine added until a slight excess was present ; the acetic acid was then removed by exposure in a vacuous desiccator, the residue dissolved in ether, the solution decolorised with charcoal, and sufficient light petroleum added to cause slight turbidity on standing. I n this way, colourless crystals of a bromo-derivative melting above 250' were obtained ; this, after recrystallisation from ether and petro- leum, was analysed by Carius' method. 0,116 gave 0.0568 AgBr. Br=20*9. C,,H1,O,Br requires Br = 21.6 per cent. Action of Bromine on PicropodopylZin.A bromo-derivative of picropodophyllin was formed on treating it with bromiue in the same manner as podophyllotoxin, but it could not be obtained in a crystalline condition except from alcohol, and solution in this liquid was always accompanied by liberation of free bromine, A specimen which had been crystallised from alcohol was dissolved in ether, and the solution fractionally precipitated with light petroleum ; the second fraction was colourless and melted a t 13S0, and no change in the melting point wits observed after fractional precipitation from218 DUNSTAN AND HENRY: A CHEMICAL INVESTIGATION OF THE ether. result. A portion of this specimen was analysed, with the following 0.0347 gave 0.0143 AgBr. This monobromopicropodophyllin, therefore, appears to be an iso- Br = 18.85 C,,H,,O,Br requires Br = 21.6 per cent.meride of monobromopodophyllotoxin. Action of Nitric Acid on Podophgllotoxin and on Picropodophyllin. On adding strong nitric acid to podophyllotoxin dissolved in glacial acetic acid, a deep red coloration was produced, which, after a few hours, changed to deep yellow; after the nitric and acetic acids had been partly removed by heating on a water bath, a colourless, crystal- line substance separated, which was shown to be oxalic acid by an analysis of the silver salt. Found Ag = 70.5. It should be added here that the substance melted at 100" before drying, and at 187" after drying, which is characteristic of oxalic acid. The residue left after complete removal of the nitric acid and acetic acid was an amorphous, yellow resin ; from this, no crystalline sub- stance could be isolated.Picropoclophyllin was found to yield exactly the same products as podophyllotoxin when attacked by nitric acid. Ag,C20, requires Ag = 70.8 per cent. Distillation of PodophJlotoxin with Zinc Dust. When podophyllotoxin is niixed with a large excess of zinc dust and the mixture heated to redness in a tube, a small quantity of a yellow oil is obtained ; by using considerable quantities of podophyllotoxin, enough of this oil was finally accumulated for analysis, It was puri- fied by dissolving in ether, and after shaking with dilute alkali, which removed some phenolic substance, the ether was distilled off, the last traces being removed by exposure in a vacuum, and the oily residue distilled.The portion boiling between 256" and 258' (about 80 per cent. of the product) was pale yellow, and had a slight phenolic odour ; when exposed to the air for several days, it darkened and somewhat resitiified ; on adding picric acid to its ethereal solution, it became deep red and deposited orange-red crystals melting a t 134' (dimethyl- naphthalene picrate melts at 136'). The oil gave the following numbers on analysis. 0,1547 gave 0.5181 CO, and 0.1 166 H20. C = 91.3 ; H= 8.3. Dimethylnaphthalene requires C = 92-2 ; H = 7.69 per cent,CONSTITUENTS OF INDIAN AND AMERICAN PODOPHYLLUM. 21 9 Picropodophyllin also furnishes dimet hylnaphthalene when distilled with zinc dust. The Colouring Mcdter. The residue left after removal of the ether from the ethereal solu- tion obtained from the resin previously extracted by chloroform was treated with a small quantity of ether t o remove resinous substances.The residue was then dissolved in hot glacial acetic acid, from which, on cooling, it crystallised in needles ; these were then recrystallised from ether and chloroform. Prepared in this way, the colouring matter has the appearance of ordinary quercetin, and agrees with it in pro- perties and composition. Analysis gave the following numbers. 0.1239 gave 0.2730 CO, and 0.042 H,O. C = 60.09 ; H = 3.71. 0.1034 ,, 092893 CO, ,, 0.034 H,O. C = 60.44 ; H= 3.46. C,,H,,O, requires C = 59.6 ; H = 3.31 per cent. A compound of the colouring matter with sulphuric acid was pre- pared according t o the method described by A.G. Perkin (Trans., 1895, 67, 647), the addition of sulphuric aaid to a saturated solution of the colouring matter in hot acetic acid ; on cooling, this solution deposited rosettes of a brilliantly orange coloured compound. These crystals were dried on a porous tile, and after being exposed for some time in a vacuous desiccator to remove acetic acid, were decomposed with water, and the amount of sulphuric acid libarated determined by titration. 0.112 gave sulphuric acid requiring 8.9 C.C. N/5 soda for neutralisa- tion. S=8*196 per cent. 0.075 gave sulphuric acid requiring 1.9 C.C. N/5 soda for neutralisa- tion. S = 8-11 per cent. C,,Hlo07H2S0, requires S = 8.0 per cent. The colouring matter in the first case was collected on a tared filter, washed, dried a t llOo, and weighed.0.1 12 gave0.0849 colouring matter = 75.803 per cent. C,,H,,07H,S0, requires 75.5 per cent. Action of Acetic Anhydyide. - About 1 gram of the colouring matter was heated on the water bath for about 2 hours with 4 C.C. of acetic anhydride and some anhydrous sodium acetate ; the mixture was then poured into excess of water, the precipitate collected, and after repeatedly washing with water, was dissolved in hot alcohol, the solution decolorised with charcoal, and set aside. On cooling. the substance crystallised out in silky masses of long needles, which, after recrystallisation from alcohol, melted at 192" ; pentacetylquer- cetin melts at 192O.220 DUNSTAN AND HENRY : A CHEMICAL 1NVESTIGATION OF THE I I from j combustions.It was analysed by dissolving it in a mixture of sulphuric and acetic acids, precipitating with water, and weighing the colouring matter which separated on cooling, 0,1586 acetyl derivative gave 0-093 colouring matter = 58.65 per cent. Acetylquercetin, C,,H,07(C,H,0),, requires 58.98 per cent. Action of Fused Potash.-About 0.5 gram of the colouring matter was heated with 10 grams of potassium hydroxide dissolved in 5 C.C. of water for about 20 minutes. The dark chocolate-brown '' melt " was dissolved in water, neutralised with dilute sulphuric acid, and extracted with ether ; the ethereal solution was distilled, the residue dissolved in water, and after the solution had been decolorised with animal charcoal, lead acetate was added, and the white precipitate thus formed was collected, decomposed with dilute sulphuric acid, and the mixture extracted with ether.The ethereal solution deposited colour- less crystals melting at 1 9 2 O , and an aqueous solution gave a green coloration with solution of ferric chloride. It was therefore poto- catechuic acid (m. p. 193'). The filtrate from the lead acetate precipitate was mixed with dilute sulphuric acid, the mixture extracted with ether, the latter distilled off, and the residue dissolved in water ; this solution contained ph2oro- glucinol, as, on the addition of hydrochloric acid, it stained a pine shaving a deep magenta colour. Methykution of the Colouring Mutter.-The methylic ether of the colouring matter was obtained by boiling a solution in methylic alcohol with potash and methylic iodide for about 15 hours on the water bath; the exceys of methylic iodide was then removed by dis- tillation, the residue boiled with benzene, the solution filtered, and the benzene distilled off.The residue, on crystallisation from hot methylic alcohol, gave a mass of glistening, yellow needles melting at 156'; quercetin methyl ether melts at 157'. Acetyl derivative. Colonring matted C,,HI007 of Podophyllunii cinodi m. p. 195" col. matt. = 58'65 pel cent. protocatechuic acid and phlo- roglucinol Quercetin (fromi C,,H,,O, lm. p. 195" quercitron bapk) col. matt. = 58.98 pel 1 cent. I I m. p. 166" Potash fusion Methyl Of products. 1 ether* 1 cz:2nd. protocatechuic acid and phlo- roglncinol I I m. p. 158" S=8 per cent. col. matter = 75.5 per cent.orange rosettes S=8'196 per cent. col. matter = 75.893 per cent. orange rosettesCONSTITUENTS OF INDIAN AND AMERICAN PODOPHY LLUM. 221 This experimental evidence leaves no doubt that the yellow colouring These facts tabulated as page 220. Professor Hummel kindly undertook to ascertain the value of Podo- phyllum emodi as a dye-stuff, He has compared it with quercitron bark and states that the results are most satisfactory. It is therefore probable that this plant will prove to be of commercial value as a dye-stuff and as a source of the dye quercetin, in addition to podo- phyllin. matter of the rhizome of Podophyllum emodi is puemetin. Podoph yllo-resin. The physiological action of the resin left after exhaustion of ‘podophyllin’ with chloroform and with ether showed that it still contained some substance which was very active as a purgative, al- though all the podophyllotoxin had been removed.The only solvent for this resinous residue was alcohol, and by fractional precipitation of such a solution with water, it was found possible to separate the residue into two fractions, one a soft, transparent, brownish-red resin, and the other a black powder almost insoluble in alcohol and contain- ing calcium and magnesium. The former of these two was found to be active as a purgative, and has been named provisionally podoplAyllo- yesin, whereas the latter is quite inert. All attempts to isolate a crystalline substance from podophyllo-resin failed, and as it was impossible to ensure its homogeneity, attention was turned to its derivatives in the hope of obtaining some crystalline substance which could be purified, and the analysis of which could be utilised for the determination of the composition of the active resin.Action of Acetic Anhydride on Podophyllo-resin.-About 0.5 gram of resin was boiled for about an hour with acetic anhydride and sodium acetate, the mixture poured into excess of water, allowed to stand for some hours, and the precipitate after being collected and washed with water, was dissolved in boiling alcohol, the solution decolorised with animal charcoal, and set aside. On cooling, a white, somewhat gela- tinous, precipitate formed which under the microscope was seen to consist of rosettes of crystals ; this was recrystallised from alcohol, in which it is sparingly soluble even on boiling.The recrystallised sub- stance melted at 198” and the melting point was not altered by further recrystallisation, 0.1328 gave 0,3023 CO, and 0.0667 H,O. C = 62-12 ; H = 5.57. 0.1217 ,, 0.2787 CO, ,, 0.0560 H,O. C=62.44; H=5.09. Mean C = 62.28; H = 5.33. C,,H,,O, requires C = 62.7; H = 5.8 per cent. The amount of acetic acid produced on hydrolysis was determined. For this purpose, after a weighed quantity had been boiled with N/10222 DUNSTAN AND HENRY: A CHEMICAL INVESTIGATION OF THE soda solution for several hours, it was acidified with dilute sulphuric acid, and the acetic acid distilled off. 0,1251 acetyl derivative gave 0.0474 acetic acid= 38.6 per cent. C12H,,0,(C,H,0), requires 39.4 per cent. The resin therefore probably has the formula Cl,Hl20, or Action of Pused Potash on Podophyllo-resin.-About 0.3 gram of the resin dissolved in 5 grams of potash and 2 C.C. of distilled water was heated for half an hour ; the melt was then dissolved in water, neutral- ised with dilute sulphuric acid, and the mixture shaken with ether.The ethereal solution was distilled, the residue dissolved in boiling water, and lead acetate solution added; the white precipitate thus formed was decomposed by dilute sulphuric acid, the mixture shaken with ether, and the ether removed by distillation, when a residue was obtained which became crystalline after a time. This residue, when dissolved in water, gave a green coloration with ferric chloride, and therefore contained protocutechuic acid, but the recrystallised residue melted at 200" (protocatechuic acid melts a t 193").It was therefore probable that some other substance was present, and in order to determine what this was, a larger quantity (about 2 grams) of the resin, which, however, was not quite so pure as the specimen first experimented with, was fused with potash ; the crystalline residue in this case was separated into two fractions, one melting a t 210" and the other at 192' (protocatechuic acid). Enough of the former could not be obtained for analysis, but the melting point, and the fact that it gives no coloration with ferric chloride solution and is pre- cipitated by bromine water, makes it probable that it is parahydroxy- benxoic acid (m. p. 2 1 0 O ) . The presence of this substance has already been noted among the products of the decomposition of podophyllin by fused potash (Guareschi, Ber., 1879, 12, 683).C12Hl OO,(OH),* Constituents of Podophyllunr peltatum. The whole of the work described above in connection with Podo- phyllum emodi has been repeated with the rhizome of Podophyllum peltaturn. The constituents of the two plants are identical, but the proportions in which they occur differ considerably. Thus, estimation of the amount of the crude substance 'podophyllin' contained in the two rhizomes shows that the American rhizome may contain from 4 t o 6 per cent. and the Indian rhizome from 10 t o 12 per cent. These results are referred t o in the last section of the paper.CONSTITUENTS OF INDIAN AND AMERICAN PODOPHY LLUM. 223 Constitution of Podophyllotoxin, Picropodophyllin and Picropodophyllic Acid, The facts which have been recorded make it possible t o discuss the constitution of podophyllotoxin, picropodophyllin and podophyllic acid.There is little doubt t h a t podophyllotoxin and picropodophyllin are isomerides, and that the latter is the lactone or anhydride of podophyllic acid, into which it has been converted and from which it has been obtained. It has been shown that podophyllotoxin, when dissolved in alkalis, passes into a salt of this acid, and that on heating this acid picropodophyllin is produced, which reverts to the acid again when dissolved in alkalis. There is no evidence t o show that podophyllotoxin changes into picropodophyllin before i t passes into the acid, although this may be suggested as highly probable, since picro- podopliyllin, and not podophyllotoxin, is formed when the acid is dehydrated.The nature of the isomerism of podophyllotoxin and picropodophyllin is at present obscure ; the chief difference between the two compounds is that podophyllotoxin is laevorotatory, whilst picropodophyllin is optically inactive, podophyllic acid is, however, like podophyllotoxin, laevorotatory. The principal facts which must be represented by any structural formula for podophyllotoxin are (1) the composition expressed by the empirical formula C,,H,,O,, (2) the optical activity, (3) the exis- tence of two methoxyl groups, (4) the hydration by alkalis producing an unstable acid, (5) the formation of a monobromo-derivative, (6) the production of orcinol and acetic acid on fusion with potash, (7) the production of oxalic acid on oxidation with nitric acid.We believe that these facts are satisfactorily represented if podophyllotoxin and its congeners are regarded as the derivatives of a hydrogenated pyronecarboxylic acid. It appears highly probable that podophyllic acid is the carboxylic acid of a dimethoxymethyl-phenylhydro-y-pyrone, of which picropodophyllin is the lactone, whilst podophyllotoxin must have a very similar constitution ; possibly it is an optically active form of the racemic lactone. We therefore propose the following formulae for these substances. OH VO,H \ c*3 Podophyllic acid. Picropodophyllin.224 DUNSTAN AND HENRY : A CHEMICAL INVESTIGATION OF THE Since quercetin accompanies podophyllotoxin in the plant, it is inter- esting to recall the fact that, according t o Herzig and others, quercetin is also a derivative of a phenylated pyrone.Edimation of I L PodophyZZin ” and ‘( Podophyllotoxin ” in P. emodi uncl P. peltaturn. Podophyllin.-As the rhizome of podophyllum is chiefly used for the preparation of Resina podophylli (podophyllin), the estimation of the amount of resin in the rhizome is of some commercial importance. The process of estimation used consisted in taking a weighed portion of the powdered rhizome, extracting this in a Soxhlet percolator with boiling absolute alcohol, evaporating the percolate to a thin syrup, adding excess of water, and allowing the precipitated resin to settle. The water was then poured off, the process being repeated until the water ceased to extract any sugar.The resin was then dried at 100Oand weighed. The following is a tabular statement of the amounts of resin con- tained in samples derived from different districts of the Punjab. District. Percentage of resin. Kulu ................................... 9.55 Bashahr ................................. 9.003 Mature roots ............ 11.12 Young roots 12.03 Chamba { Hazara ................................. 9-06 ............... Estimations of resin in four specimens of the rhizome of Yodophyllum peltaturn gave respectively 4.17 per cent., 5.2 per cent., 5.4 per cent., 5.2 per cent. Dymock and Hooper (loc. cit.) found 10 per cent. of resin in the Indian rhizome, and Umney (loc. cit.) 12 per cent. 1’odophyllotoxin.-An attempt was first made to estimate directly the amount of podophyllotoxin in podophyllum rhizome by percolation with suitable solvents, but this had to be abandoned owing to the difficulty of purifying the material without loss.The conversion of podophyllotoxin into its very insoluble and easily purified isomerido picropodophyllin next suggested itself as an indirect method of estimation, and preliminary experiments showed that by taking a weighed quantity of podophyllotoxin and converting it into picropodophyllin by treatment with lime, 98 per cent. of the amount taken could be recovered in the form of picropodophyllin. The process finally adopted is carried out as follows. A weighed quantity of the ground rhizome dried at 100” is mixed with lime, and the mixture percolated with chloroform in a Soxhlet extraction apparatus, the residue left on evaporating the chloroformCONSTITUENTS OF INDIAN AND AMERICAN PODOPHYLLUM.225 solution to dryness is dissolved in absolute alcohol, the solution made into a thin paste with slaked lime, and the whole evaporated to com- plete dryness; more alcohol is then added, and the process repeated. The dried residue is then mixed with absolute alcohol, the mixture boiled and filtered through a jacketed funnel, and the residue and the filter paper containing it, after being allowed to dry Bomewhat, is packed into an extraction apparatus, percolated with alcohol, and the percolate mixed with the original alcoholic filtrate ; the mixed liquids are then evaporated to dryness in a tared dish and the residue of picro- podophyllin weighed.The residue thus obtained is almost colourless and is usually well crystallised, but contains a small quantity of calcium picropodophyllate due to incomplete dissociation of the salt during the drying of the chloroform extract with lime. On incineration, the residue gives on an average about 1 per cent. of calcium oxide, but as this is responsible for only a very small error in an estimation, it may be neglected. The following table includes the results of a series of estimations of podophyllotoxin in Indian and American podophyllum, and for convenience of comparison the percentages of resin (podophyllin) are also given. Quantity of Percentage of District yielding rhizome podophyllotoxiu Percentage of the specimens. used. found. resin found. Kulu ............... 11.92 grams 2.8 15.17 ,, 2.9 Bashahr 32.46 ,, 3.5 27.12 ,, 3.6 Chamba. 10.97 ,, ......... .......... emodi. Young yoots ... { 13.46 ,, 5.3 5‘17 I Old roots ...... ,, 4.51 11.12 I Hazara ............ 11.6 ,, 2.9 14.5 ,, 3.08 0-77 12.02 ” 0.82 0.995 4.1 7 peltatum. 22.6 23’55 1 ” 5‘2 1 Podop?u$um 1 United States of 11.35 America Taking the average yield of resin and of crystallised podophyllotoxin from the rhizome of PodophpZZum e m d i to be 10 per cent, and 3.5 per cent. respectively, the amount of podophyllotoxin in podophyllin from the Indian drug must be about 38 per cent., whilst that contained in American podophyllin is only about 20 per cent., although in extracting podophyllotoxin itself from the plant nothing like this quantity is obtained, owing to the difficulty experienced in purifying it from the 8 VOL. LXXIII226 DUNBTAN AND HENRY : THE VOLATILE viscous resinous substances also removed by the solvents. Although there is a difference of nearly 20 per cent. in the amount of podophyl- lotoxin contained in the podophyllin from these two sourcea, it is remarkable that they differ comparatively little in physiological activity, a fact which supports the view that podophyllotoxin cannot be regarded as the only active constituent of the resin. Since the Indian resin contains morc podophyllotoxin than the American, it behaves somewhat differently when warmed with alkalis, owing to the larger amount of the insoluble picropodophyllin which is formed and crystallises out. The test of the British Pharmacopceia, which requires podophyllin to be soluble in aqueous ammonia, there- fore needs modification. In preparing the ammoniacal tincture from the Indian resin, the mixture should not be heated. Nor, indeed, should heat be used in any case in preparing the tincture, since even with the .American resin some of the active podophyllotoxin will be changed into the inert picropodophyllin. SCIENTIFIC DEPARTMENT, IMPERIAL INSTITUTE, LONDON.

ISSN:0368-1645    

DOI:10.1039/CT8987300209

出版商:RSC    

年代:1898

数据来源: RSC

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226 DUNBTAN AND HENRY : THE VOLATILE XV1.-The Volatile Constituents of the Wood o f Goupia tomentosa. By WYNDHAM R. DUNSTAN, F.R.S., and T, A. HENRY, Salters’ Research Fellow in the Laboratories of the Imperial Institute. Goup“ tmnentoaa is a large tree growing in British Guiana, where it is known as Kabucalli,” and used in the colony for boat-building ; it has recently been sent with other timbers by the Government of the Colony to the Scientific Department of the Imperial Institute, so that its general merits as a timber might be ascertained. The timber has been submitted to mechanical tests by Professor Unwin, F.R.S., in the course of an examination of the various timbers of British Guiana which he has conducted for the Imperial Institute. An account of these tests has been published (Imperial Institute Journal, 3, p.51). When the log sent from the colony was cut, the:wood was seen to be reddish, very hard, with a fine, close grain. When first cut, it emitted a strong odour resembling that of valeric acid, and when shaved with a plane, the cut surface became covered with a thin film of oil. On account of these peculiarities, it was decided to examine its chemical constituents ; for this purpose, the wood was cut up into fine shavings, which were at once placed under water, and, after standing aboutCONSTITUENTS OF THE WOOD OF GOUPIA TOMENTOSA 227 12 hours, were steam distilled. The distillate was then concentrated by steam distillation, and the process repeated until fatty particles began to separate from the distillate; the liquid was now shaken with ether, and the ethereal solution dried with calcium chloride and distilled.I n this way, a dark-coloured oil was obtained, which became semi-solid on cooling ; this was dissolved in boiling alcohol, and decolorised with animal charcoal ; on cooling, the filtered solution deposited a colourless, fatty substance, which was obtained in small needles by repeating the process. When pure, i t melted at 45'; it distilled under reduced pressure, and was slowly dissolved by alkaline solutions, and reprecipitated from them by acids. A combustion of the pure material gave the following result. 0*1624gave:0*4281 C02and0.1783 H20. C = 72.04; H= 12.19percent. Lauric acid, C12H2402 requires C = 72 ; H = 12 per cent. A sodium salt was prepared by exactly neutralising an alcoholic solution of the acid with alcoholic soda and evaporating the solution in a vacuous desiccator over potash.A white precipitate slowlp separated, and this, on analysis, gave the following result. 0.142 gave 0.0450 Na2S0,. The substance therefore agrees in composition and properties with lauric acid (m. p. 43.6'). This acid occurs, usually as the glyceride, in many plants, but notably in the oils obtained from the fruit of Laurus nobilis and Cocoa nucvera. As lauric acid is only slightly volatile in steam, its isols- tion by steam distillation is extremely tedious, and having identified it, an attempt was made t o obtain it by extracting the wood shavings with ether ; this, however, was not found to be feasible, owing to the large amount of resin also removed by the ether, and from which it is very difficult to isolate the lauric acid by crystallisation.The aqueous distillate left after extraction with ether was made strongly alkaline with solution of soda, evaporated to dryness over the water bath, and then acidified with dilute sulphuric acid ; the oil which separated was removed by ether, the ethereal solution dried with calcium chloride, the ether distilled off, and the residue fraction- ated several times ; in this way, three fractions were obtained, boiling respectively at about 46O, 150°, and 206'. The first of these fractions was very small; it had a pungent odour, and its aqueous solution reduced silver nitrate and mercuric chloride, It probably, therefore, contained formic acid, but enough could not be obtained for complete identification.The fraction boiling at about 150' was dissolved in dilute soda Na- 10.2 per cent. C,,K2,0,Na requires Na= 10.4 per cent. Q 2228 CONSTITUENTS OF THE WOOD OF GOUPIA TOMENTOSA. solution and the solution evaporated ; two fractions of crystalline sodium salt were obtained. These were converted into the silver salts, the second fraction of sodium salt being precipitated in two portions with silver nitrate; the silver salts, on analysis, gave the following numbers. First fraction of sodium salt gave a silver salt containing 48.6 per cent. Ag. Second fraction of sodium salt gave two fractions of silver salt, A and B. A, containing 49.9 per cent. Ag ; B, containing 50.6 per cent. Ag. I n a second experiment, in which a larger amount of sodium salt was obtained, the crystals were separated into two fractions, and these again fractionated by addition of silver nitrate solution; the first fraction of silver salt contained 48.3 per cent.Ag. From the results of these analyses, and the properties of this fraction of oil, it evidently consists of a mixture of isovaleric and caproic acids. Silver isovalerate requires 51-4 per cent. Ag. Silver caproate requires Ag = 48.2 per cent. The fraction of oil boiling a t 206O, which constituted about 60 per cent. of the whole, had all the properties of normal Ibexoic (caproic) acid, but it mas not quite pure, since on conversion into the sodium salt and fractional precipitation of the solution of this salt with silver nitrate, some fractions containing 56 to 58 per cent.of silver were obtained, but the greater portion of salt contained 47.82 per cent. of silver. The oil was therefore redistilled very slowly, and the first portion, which boiled almost constantly between 206" and 209O, collected. Normal caproic acid boils a t 206O, and silver caproate contains 48.2 per cent. of silver. The oily residue left after the redistillation of the second fraction of oil became coloured on further heating, and it was strongly acid to litmus. The residue was dissolved in ether, decolorised by animal charcoal, and the ether distilled off ; the oil, on being allowed to stand for some months, deposited a small quantity of a crystalline substance. These crystals were removed, dried first on a porous tile and then at 100".The substance melted at 180°, and sublimed when heated gently in a test tube.; it was acid to litmus. The whole of the material obtained was converted into the silver salt, and the latter ignited, with the following result. 0.0082 gram gave 0.0051 Ag. This agreement is as good as can be expected, aince the quantity Ag = 62.2 per cent, Silver succinate requires Ag = 64.4 per cent.PRODUCTION OF SOME NITRO- AND AMIDO-OXYLUTIDINES. 229 ___._ Fraction I. Formic acid P available for analysis was so small that a difference of one unit in the fourth decimal pJace causes an error of 1 per cent. in the result. The properties of the substance leave little room for doubt that it is succinic acid (m. p. 180’). - - Fraction 11. Isovule& acid, Ll’ornzul caproic mid. SUMMARY OF SEPARATION OF CONSTITUENTS. Wood, steam distilled. Concentrated distillate extracted with ether. I Residual distillate made alkaline and evaporated made acid and oil separated I Fraction 111. Noymal caproic acid and Succinic cccid. Ether solution leaves viscid oil containing SCIENTJFIC DEPARTMENT, IMPERIAL INSTITUTE, LONDON, S.W.

ISSN:0368-1645    

DOI:10.1039/CT8987300226

出版商:RSC    

年代:1898

数据来源: RSC

摘要:

PRODUCTION OF SOME NITRO- AND AMIDO-OXYLUTIDINES. 229 XVII.-P~od~uction of some Nit?-o- rind Amido- oxylutidincs. Part 1. By PROF. J. N. COLLIE, Ph.D., F.R.S., and THOMAS TICKLE, Salters’ Company’s Research Fellow in the Research Laboratory of the Pharmaceutical Society of Great Britain. I n a former paper (Trans., 1897, 838), one of the authors has drawn attention to the fact that nitro- and amido-derivatives of pyridine can be obtained from oxypyridine compounds by the ordinary process of nitration and reduction. As these substances correspond in the pyridine series t o nitro- and amido-phenols i n the benzene series, their reactions and properties are of some interest, and i t has been considered worth while to continue the investigation, using a hydr- oxylutidine (pseudolutidostyril) as the starting point,230 COLLIE AND TICKLE: PRODUCTION OF SOME A CH,*E ?*OH HC CH CH3 Pseudolutidostyril.This compound, uy-dimethyl-u'-hydroxypyridine, is easily nitrated when treated with a mixture of strong nitric and sulphuric acids, yielding a nitropseudolutidostyril, which, on reduction with tin and hydrochloric acid, gives a n amidolutidostyril. As, however, the entering nitro-group might replace either of two different hydrogen atoms, i t was necessary to determine if possible the exact composition of the new nitro-derivative. I. 11. /N\ CH3*E F*OH /" CH *s ?*OH could CH,*E ?-OH ol' HC CH give H C C-NO, NO,*C CH \& I \ C / I CH, CH, That the substance had the molecular structure represented by the formula I. was proved by obtaining it from ethylic nitroluditostyril- carboxylate (Trans., 1897, '71, 301).A CH,*;C; $!*OH CH,*fi F*OH C'O@C,H,*C CH -3 COOC,H,*C C*NO, 3 HC ONO, A \ C / I \(+ I \f CH,*E ?*OH CH, crr, CH, When this nitrohydroxylutidine is subjected to the reducing action of tin and hydrochloric acid, it is at once converted into the correspond- ing amidohydroxylutidine. In a former paper by one of the authors (Trans., 1897,71, 842), an amidodihydroxypicoline was similarly prepared, and it was then noticed that the dioxy-compound suffered a somewhat curious change when boiled, passing into a trihydroxypicoline :-- CH,* C,NH(OH),*NH, + H,O = CH,. C,NH(OH), + NH,. This reaction is different from any that amidophenols undergo, but is similar t o the formation of orthonitrophenol from orthonitr- aniline when the latter is boiled with alkalis ; possibly i t may be dueNITRO- AND AMIDO-OXYLUTIDINES.PART I. 231 to the ease with which, in a-hydroxypyridine compounds, the ring binding can be loosened and opened out (Trans., 1897, '71, 839). We were in hopes, that as the amido-group and the hydroxy-group in the amidohydroxylutidine were in the same relative positions (namely, a and p), the same reaction might again occur, and the corresponding dihydroxylutidine derivative be formed, but although many attempts were made no such change could be effected. The nmidohydroxylutidine is a substance with characteristic proper- ties, it is very unstable and cannot be heated to 100' without turning brown; it rapidly reduces solution of nitrate of silver and platinic chloride.With ferric chloride, it gives first a red and then a bright green coloration, but it does not yield the series of brilliant colour re- actions in alkaline solution like the trihydroxypico1ine:mentioned above (Trans., 1897, 71, 843). When, however, it is dissolved i n strong sulphuric acid and a drop of nitric acid is added, a strong purple colora- tion is produced similar t o that which strychnine gives when treated with sulphuric acid and potassium dichromate. I CH3 The pseudolutidostyril employed was prepared from ethylic P-amido- crotonate according to the method given in a former paper by one of the authors (Trans., 189'7, 71, 299); it was found convenient only to nitrate small quantities of the substance at a time. Three to four grams of the pseudolutidostyril were dissolved in 6 C.C.of sulphuric acid, and this mixture was then slowly added to 8 C.C. of a mixture of sulphuric and fuming nitric acids, which were kept well cooled : large quantities are less easily manageable, the temperature being liable to rise suddenly, when the whole of the substance is destroyed by oxidation. The mixture is then diluted with 10 times its volume of water, the new nitro-derivative which separates in yellow needles being most conveniently recrystallised from 30 per cent. acetic acid, or a mixture of 30 per cent. acetic acid to which about 3 per cent. of nitric acid has been added. When pure, it crystallises in light yellow needles that melt somewhere about 250' if suddenly heated to that temperature, but if the heating be slow, the crystals darken a t about 243' and then rapidly decompose.On analysis, the following numbers were obtained : C. H. N. Found .... ............ ... ...... ... 49.8 5.4 17.5 Calculated for C7H,N,0,.. , . . 50.0 4.8 16.7232 COLLIE AND TICKLE: PRODUCTION OF SOME No other nitro-compound seemed to be present, and the only sub- stance produced by the nitration of pseudolutidostyril was the com- pound mentioned above. It is not volatile with steam, and with alkalis, it gives brilliant yellow compounds. Amidoiosezcdol.utidostyri1, C,NH( CH,),( OH) N H,. When the nitro-derivative of pseudolutidostyril is reduced with tin and hydrochloric acid, the hydrochloride of amidopseudolutidostyril is formed, the reaction being accompanied by a considerable evolution of heat.After precipitating the tin by means of hydrogen sul- phide, the solution is evaporated on the water bath, when the hydro- chloride of the base begins to separate as soon as the solution becomes concentrated. A second method for preparing the hydrochloride was used ; if, after the reduction with tin and hydrochloric acid, the solution is evaporated, a well crystallised double salt of the hydrochloride of amidopseudolutidostyril and tin chloride separates ; this can be purified and then its solution decomposed by means of hydrogen sul- phide. By either method, a white salt was obtained crystallising in needles, and decomposing without melting at 235-240°, but like the nitrolutidostyril, if suddenly heated to about 300°, it can be partially molted before decomposition ensues.It was analysed. C. H. N. c1. Found ........................... 47-8 6.4 20.3 19.6 Calculated for C7H,,N,0,HCl 48.1 6.3 20.3 20.3 The substance, therefore, is a monhydrochloride, Whenthis hydrochloride is treated in aqueous solution with sodium hy- drogen carbonate, it is converted into the free base, which is less soluble and separates in the form of a bulky mass of fine, needle-shaped crystals; these were purified by recrystallisation from water until they melted constantly at 205O (corr.). The base is very soluble in hot water but less so in cold (to the extent of 8-10 per cent. in cold), it is very unstable at looo, the dry substance rapidly turning brown when heated in a water oven to that temperature. The aqueous solution even turns brown on boiling, and in the presence of alkalis the decomposition is much more rapid.When added to a cold solution of silver nitrate, it instantly gives a black precipitate of silver, and when warmed with a little chloride of platinum reduction was found to take place; the normal platinochloride can be prepared, but in the presence of hydrochloric acid it changes into a new salt containing 3 per cent. more platinum than the normal salt. This new salt waa produced when trying to recrystallise the ordinary salt from dilute hydrochloric acid.NITRO- AND AMIDO-OXYLUTIDINES. PART I. 233 Analyses of both salts were made. The normal platinochloride contained 28.5 per cent. Pt. Calculated for (C7HloN20),,H2PtC~, 28.4 per cent, Pt. The new salt obtained from hydrochloric acid solution, on analysis, was found to give the following numbers.C. H. Pt. c1. Found .................. 20.4 3.0 31.5 34.8 Calculated for (C7Hl,N,0),,H,PtC16 120.4 2.7 31.5 34.5 c~H~~N,o,H,P~c~, J This substance appears therefore t o be a compound of the mono- and the di-hydrochlorides of the base with platinic chloride. When the amidopseudolutidostyril is heated on the water bath with acetic anhydride, it is converted into a monacetyl derivative which can be crystallised either from water or from alcohol. It is obtained in white, silky needles melting at 255' (corr.), it is neutral to litmus paper, and fairly soluble in cold, but very soluble in hot, water. Ether, acetone and ethylic acetate dissolve it more sparingly, and it differs from amidopseudolutidostyril in that it gives no reaction with ferric chloride, neither does it reduce silver nitrate solution.The amidopseudolutidostyril can be regenerated from it by hydrolysis with dilute hydrochloric acid heating the mixture under pressure in a sealed tube. It gave the following numbers on analysis. C. H. Found ............................. 60.1 6.5 Calculated for C7H9N20,C2H,0 60 *O 6.6 This is produced when ethylic pseudolutidostyrilcarboxylate (m. p. 138-139") is nitrated in the ordinary manner with a mixture of strong nitric and sulphuric acids. It is scarcely soluble in water, but can be recrystallised from acetic acid ; it then forms long, pale yellow, needle-shaped crystals, which melt without decomposition at 215' (corr.). It was analysed.C. 11. N. Found ................................ 49.7 6.1 11.6 Calculated for C,,H,2N20,. ........ 50.0 6-0 11.6234 PRODUCTION OF NITRO- AND AMIDO-OXYLUTIDINES, PART I. It is not very soluble even in hot soda solution, but, on warming, decomposition slowly occurs and the brilliant yellow sodium salt of the nitropseudolutidostyrilcarboxylic acid is produced. This nitropseudolutidostyrilcarboxylic acid was also prepared in larger quantities by nitrating the free acid. Ten grams of the acid were carefully added to 20 C.C. of well cooled fuming nitric acid, and afterwards poured into 10-15 C.C. of strong sulphuric acid ; care must be taken not to allow the temperature to rise, otherwise a violent action begins, and the substance is entirely destroyed. On pouring the mixture into cold water, the new nitro-acid separates.It was found on analysis to contain lH,O. Loss of weight at 100'=8.2 per cent. Calculated for C,H,N,O, + H,O = 7.8 per cent. The dried substance gave the following numbers. C. H. N. Found ................................. 45.3 4.2 13.3 Calculated for C,H,N,O, ......... 45.3 3.8 13.2 This nitro-acid can be recrystallised from acetic acid or water, but it is not very solublo in the latter. When pure, the crystals are almost white needles, the aqueous solution having only a faint yellowish t i n t ; when rapidly heated, they melt at 260' (corr.). The ammonium salt is easily obtained in! the crystalline condition, and is bright yellow; it gives a brown precipitate with ferric chloride, and a crystalline precipitate with silver nitrate.The lead and barium salts seem to be soluble. The moment the free acid is melted, it effervesces and evolves carbon dioxide, whilst a yellow, crystalline residue remains which melts at a temperature 10-15' below the acid ; after purification, this residue was found t o be identical with the nitropseudolutidostyril obtained by nitrating pseudolutidostyril itself and already mentioned earlier in this paper. This method for the manufacture of nitropseudo- lutidostyril was not used, because the decomposition of tho substance at the temperature at which the nitro-acid fused was very considerable. Amidopseudolutidostyrilcal.boxyZic mid, NH,. C,N(CH,),(OH)*COOH. When the nitreacid is reduced by means of tin and hydrochloric acid, the hydrochloride of the corresponding amido-derivative is produced.To prepare this substance, the nitro-acid is dissolved in strong hydro- chloric acid, and the tin is added little by little, the reduction taking place very readily with a considerable rise of temperature. The acid solution obtained after the tin has been precipitated with hydrogenPRODUCTION OF NITRO- AND AMIDO-OXYLUTIDINES. PART 11. 235 sulphide is evaporated on the water bath, and from the concentrated solution the hydrochloride separates in needle-shaped crystals ; these can be recrystallised from hydrochloric acid, but with pure water the substance is decomposed into the free acid, which is much more insoluble than the hydrochloride. The hydrochloride gave the following results on analysis.Found ... ... ... ... ... ... ...... ...... ... ... ... 37.9 6.0 11.3 14.0 Calculated for U,H1,N,O,,HC1 + 2H,O 3'7.7 5.9 11.0 13.9 The substance, when heated a t looo, lost 14.5 per cent. H,O. The calculated amount corresponding with 2H,O = 14.1 per cent. The smido-acid can be prepared by decomposing the hydrochloride with excess of water ; it is very slightly soluble even in hot water. From hot alcohol i t separates in needles, whilst if the potassium salt be decomposed by acetic acid the free acid can be obtained in the form of small flat prisms; it is insoluble in ether, acetone, and chloroform. It is unstable, turning brown rapidly when heated to looo ; the alcoholic and aqueous solutions behave in a similar manner. The amido-acid has strong reducing properties; if added to silver nitrate solution, it forms a dense grey precipitate of silver, and the solution becomes pale green. With ferric chloride, it gives a pale green coloration which rapidly deepens to emerald green, purple, and finally deep blue. With ferrous sulphate, it gives no coloration, and the calcium, barium, lead, and copper salts seem to be soluble. When very carefully heated on an oil bath, the acid melts at 2 7 5 O (corr.). It also loses, at loo", 8.7 per cent. of water. Calculated for C,H,,N,O, + H,O ; H,O = 9.0 per cent. A t its melting point, it gives off carbon dioxide, and the residue (which sublimes a t the temperature at which the decomposition occurs), after purification, was found to melt at 205O (corr.); its hydrochloride melted at about 300", and corresponded in all respects with the amido- pseudolutidostyril obtained by the reduction of the nitropseudolutido- styril. C. H. N. CI.

ISSN:0368-1645    

DOI:10.1039/CT8987300229

出版商:RSC    

年代:1898

数据来源: RSC

摘要:

PRODUCTION O F NITRO- AND AMIDO-OXYLUTIDINES. PART 11. 235 XVIII.-Productio?z o f some Nitro- and Amido- oxylutidines. Purt 11. By Miss L. HALL (University College, London) and J. NORMAN COLLIE, Ph.D., F.R.& (Professor of Chemistry at the Pharma- ceutical Society of Great Britain, London). THE production of nitro- and amido-derivatives in the pyridine series has been the subject of two former papers communicated by one of the authors to the Society (Trans., 1897, 71, 838 and 1898, 229). In236 HALL AND COLLIE: PRODUCTION OF SOME the first of these papers, it was shown that, when dioxypicoline is dissolved in nitric acid, nitration a t once occurs, and from the nitro- dioxypicoline produced, several amido- and oxy-picoline derivatives could be prepared. The present communication is a continuation of that work.The oxypyridine derivative chosen was lutidone, or aa’-dimethyl-y oxy pyridine. NH CH,* ;ci! / ‘C*CH, Hc,co/8H Lu t id one. It was found that lutidone, however, was not nitrated when treated with nitric acid alone, as was the case with the di-oxypicoline, but was only converted into the nitrate of lutidone, and a mixture of fuming nitric and sulphuric acids had to be employed before it was changed into nitrolutidone. This was the case also with pseudoliitidostyril (Trans., 1898, 230). The nitrolutidone is a very pale yellow, crystal- line compound which dissolves in alkalis with an intense yellow colour, has a strong acid reaction, and is not volatile with steam. When treated with t i n and hydrochloric acid, it is easily reduced, forming an amidolutidone.NH CH3. fi / ‘fi*CH3 HC \ ,c*m GO hmidolu tidone. This amidolutidone, unlike amidodioxypicoline and amidopseud 0- lutidostyril, does not give characteristic colours when treated with various oxidising agents, t h i s being probably due to the fact that the amido- and the oxy-group are in the ortho-position relatively to one another. It does, however, yield a brownish-red coloration with ferric chloride, but with strong sulphuric acid and potassium dichromate or with nitric acid no markedcoloration is produced. It has, however, strong reducing properties ; with nitrate of silver, it gives first a white, semi- crystalline precipitate which is entirely reduced to metallic silver on warming. It also forms two hydrochlorides, a mono- and a di-deriva- tive, and its platinochloride belongs to the class of double salts where 1 mol.of the dihydrochloride unites with 1 mol. of platinic chloride. This platinochloride is very unstable, and when dissolved in water and warmed undergoes reduction, but if its solution be warmed with hydrochloric acid, another kind of change ensues and an exceedinglyNITRO- AND AMIDO-OXYLUTIDINES. PART 11. 237 insoluble platinochloride separates, which, from its analysis, seems t o be the salt of propine-diamine, CH3*f?NHz,H2PtCI, HC*NH, The decomposition having been brought about by hydrolysis, C7HIoN2O + 3H20 = C3H,N, + 2CH3*COOH. This breaking down of the pyridine ring is one of considerable interest, and in a substance like lutidone was hardly to be expected, for the nitrogen atom is bound to two carbon atoms neither of which are united to oxygen, and lutidone is not the anhydride of an amido-acid as is the case of pseudolutidostyril. E XPE R I M E N T A L.aa'-DimethyL y-ox y - P-nitrop yridine. The lutidone used in the following experiments was prepared from dehydracetic acid by heating it in sealed tubes at 130' with excess of strong aqueous ammonia, the product being a mixture of lutidone and ammonium lutidonecarboxglate. By evaporating the contents of the tubes to dryness and subsequent distillation crude lutidone was ob- tained ; this was recrystallised from water until pure. A large number of attempts were made t o nitrate lutidone, at first with nitric acid alone, it having been found in the case of dioxypicoline to give almost quantitative yields of the nitro-derivative.A very soluble nitro-compound mas obtained which decomposed rapidly at 85'. After it had been recrystallised from water, several analyses were made, but although these agreed amongst themselves, yet, as soon a8 the substance was recrystallised from alcohol or acetic acid, the analytical numbers showed that, with each solvent, a diff erent change was being effected, and it was not until the compound was purified by recrystallisation from nitric acid that any results were obtained which could be relied upon. Found C = 45.4 and 44.9 ; H = 5.7 and 5.8 ; N = 15.2 and 15.2. Calculated for C7H,,N20,, C = 45.2 ; H = 5.3 ; N = 15.1 per cent. The substance melted at 120Owhen quickly heated to that tempera- ture, but if kept at 100' it decomposed.Attempts were made also to reduce it with tin and hydrochloric acid, and a crystalline hydrochloride was obtained, but this hydrochloride did not seem to possess the properties of an amido-oxypyridine derivative, neither did the original nitrolutidone yield yellow salts with soda or potash, Ultimately, it was found that the supposed nitro-compound was merely the nitrate of lutidone, for when neutralised with the proper quantity of caustic soda and the solution evaporated, unchanged238 HALL AND COLLIE : PRODUCTION OF SOME lutidone was recovered together with sodium nitrate ; moreover, the original substanco gave, with strong sulphuric acid and ferrous sul- phate solution, the ordinary nitrate test, whilst the supposed hydro- chloride of amidolutidone gave results agreeing with lutidone hydro- chloride, and lutidone was actually prepared from it by treatment with soda solution, Found N = 8.7 ; C1= 22.3 per cent.Calculated for C7H,N0,HCl,H,0, N = 8.7 ; C1= 22.0 per cent. The supposed nitrolutidone was, therefore, merely lutidone nitrate, Not having been able to prepare a nitro-derivative by the action of nitric acid alone, a mixture of nitric and sulphuric acids was next tried. Twenty grams of lutidone was dissolved in 30 C.C. of strong sulphuric acid and 60 C.C. of a mixture of equal volumes of fuming nitric and sulphuric acids was added ; no nitrous fumes were evolved. It was then warmed for a few moments on a water bath and when cold poured into water, and the aqueous solution nearly neutralised with sodium carbonate, pale yellow crystals at once began to separate ; these, which were nearly soluble in cold water, were washed and recrystallised from dilute acetic acid. When pure, they are nearly colourless, having only a faint yellowish tinge.The compound melts at about 290-300° with considerable decomposition. It has a strong acid reaction, and when dissolved in soda yields a brilliant yellow solution ; the yellow solution obtained by dissolving the substance in ammonia gradually loses its colour when boiled, the un- changed nitro-derivative ultimately crystallising out after all the am- monia has been driven off. This ammoniacal solution gives a brilliant yellow precipitate with silver nitrate solution. CVH,JY,O* = C,H,NO,HNOp On analysis, the following numbers were obtained.Fbund C = 49.9 and 49-$ ; H = 5.1 and 5.2 ; N = 16.7 and 16.9. Calculated for C7H,N20,, C = 50.0 ; H = 4.7 ; N = 16.6 per cent, C7H,N0 + HNO, = C7H,N,0, + H20. The compound is therefore the true nitrolutidone, ad-dime thy Z-y-oxy-P-umidopyridine. When nitrolutidone is added to n mixture of granulated tin and strong hydrochloric acid, it at once dissolves and the temperature rises considerably ; the reduction is very rapidly effected, and after the tin has been precipitated by hydrogen sulphide, the filtered liquid on evaporation yields crystals of amidolutidone hydrochloride. This salt is best recrystallised from hydrochloric acid ; it then forms a granular maas of cryatals, which, in solution, have a strongly acid reaction.OnNITRO- AND AMIDO-OXYLUTIDINES. PART XI. 239 keeping, they lose both hydrochloric acid and water. substance was dried between filter paper and analysed as soon as dry. Found C = 33.6 ; H = 6.9 ; N = 11.6 ; C1= 28.4 per cent. Calculated for C7Hl,N20,2HC1,2H,0, C = 34.0 ; H = 7-3 ; N = 11.4 C1= 28.7 per cent. An estimation was also made of the water of crystallisation, but as it loses hydrogen chloride also when heated, the result is possibly not a correct one. Some of the Found (after heating quickly a t 100') H20 = 15.0 per cent. Calculated, 2 mols. of water, H20 = 14.5 per cent. The salt melts at about 275-280O (corr.),losing a considerable amount of hydrogen chloride. When its solution is treated with only one molecular proportion of sodium hydrogen carbonate, a monohydrochloride melting at 186" (corr.) can be obtained; this, when heated at 100' for some time, decomposes and turns brown. It was recrystallised from alcohol and a nitrogen estimation made.Found N= 16e7 per cent. Calculated for C,FI,,N,OHCl, N = 16.1 per cent. Both these hydrochlorides when entirely neutralised by either soda or sodium carbonate, yield amidolutidone which is not very soluble in cold water, and can be easily purified by recrystallisation from water. It crystallises in long, needle-shaped crystals, and when analysed gave the following results. Found C = 52.7 ; H = 7.9 ; N = 17.8 per cent. Calculated for C7H,,N20,H20, C = 53.8 ; H = 7.7; N = 17.9 per cent. The substance was also dried at 100° and analysed. Found C = 60.1 ; H = 7.7.Calculated for C7H10N20, C = 60.9 ; H = 7.3 ; N = 20.3 per cent. Two determinations of the water of crystallisation were also made. Found H20 = 11.7 and 11.5. Calculated for 1H20, 11.5 per cent. This amidolutidone, as has already been pointed out, does not yield such a brilliant series of colour tests, when treated with various oxidising reagents, as either the amidodihydroxypicoline or the amido- pseudolutidostyril. It does, however, give a brownish-red coloration with ferric chloride, and with strong sulphuric acid and solid potassium dichromate a green colour. Its chief characteristic property is its reducing power ; when silver nitrate is added to its aqueous solution, a voluminous, white precipitate is formed at first, but on warming complete reduction occurs, and metallic silver is produced as a N = 20.6 per cent.240 PRODUCTION OF NITRO- AND AMIDO-OXYLUTIDINES.PART 11. grey metallic deposit, in this respect it resembles the amidodihydroxy- picoline. If amidolutidone is persistently boiled with carbonate of soda solution, it is partially decomposed, and some acetate can be detected in the solution, and instead of giving the platinochloride of amido- lutidone, another platinum salt was obtained containing 37.5 per cent. Pt. This agrees with C,HloN20,H2PtC16 ; Pt = 37.2 per cent. The de- composition may possibly have occurred as follows, C7Hl0N,O + 2H,O = C,H,,N,O + C2H40,. The true platinochloride of amidolutidone is a very soluble salt, and is best prepared by pouring a strong solution of platinic chloride on to solid amidolutidone hydrochloride.It then crystallises in small, very characteristic, microscopical, shield-shaped crystals ; these cannot be recrystallised from hot water, as they entirely decompose when warmed in aqueous solution. Found Pt = 32.3 and 32.7; water of crystallisation, H,O = 5.9 per cent. Calculated for C7HloN,0,H,0,H,PtCI, + 2H,O, Pt = 32-4 ; 2H,O =5*9 per cent. When this platinum salt is dissolved in dilute hydrochloric acid and the solution is warmed, a granular platinum salt begins to separate after a short time ; this is only sparingly soluble, even in hot water, its hot aqueous solution also, if not acid with hydrochloric acid, undergoes reduction on boiling, and the dry salt, when heated, chars, but does not melt. When dried, it contains as much as 40.2 per cent.of platinum, thus showing that it must not only be the platinum salt of a base with a very small molecular weight, but also that the base must belong to the class of diamines. Found C = 7-2 ; H = 2.2 ; N = 5.9 ; Pt = 40.2, 40.3, 40.5 per cent. Calculated for C,H,N2,2HCI,PtCl4, C = 7-53 ; H = 2.4 ; N = 5.6 ; The undried salt contained H20 = 3.8. Calculated lH,O = 3.6 per This curious platinum salt was, therefore, evidently the salt of They were analysed. The salt was dried at 100' and analysed. Pt=40*2 per cent. cent. ; also 39.1 per cent. Pt ; calculated, Pt = 39.0 per cent. propinediamine, CH3* $ "H2,H2PtCl,, and this diamine had been pro- H.C *NH, duced by the decomposition of the amidolutidone, C7HIoN,O + 3H,O = C,H,N, -I- 2C,H402. But it is remarkable that such a change should occur, especially as lutidone itself is such a stable pyridine compound, and is not liable to be reconverted into open chain compounds. An attempt was made, but without success, to prepare the free base, propinediamine, fromNOTE ON THE ACTION OF BROMINE ON BEKZENE. 2.11 the platinum salt by precipitating the platinum with sulphuretted hydrogen and subsequently evaporating ; the residue of the hydro- chloride was excessively soluble in water, and when treated with soda gave some ammonia gas, and the solution at once reduced silver nitrate solution, but owing to the small quantity of the platinum salt at our disposal, we were unable to isolate the free base.

ISSN:0368-1645    

DOI:10.1039/CT8987300235

出版商:RSC    

年代:1898

数据来源: RSC

摘要:

NOTE ON THE ACTION OF BROMINE ON BEKZENE. 2.11 XIX.-Note on the Action of Bromine on Benzene. By J. NORMAN COLLIE, Ph.D., F.R.S., and COLIN C. FRYE, Pharma- ceutical Society of Great Britain, Bloomsbury Square. IN a former paper communicated to the Society (Trans., 1897, 71, 1013), one of the authors referred to a paper by Ador and Rilliet (Ber., 1875, 8, lZSS), where it was stated that, by the action of a small quantity of bromine on excess of benzene, bromine additive products are formed, which, on treatment with zinc ethide and subsequent oxidation yield metabromophthalic acid and metaphthalic acid. The re- action was supposed to take pIace according to the following equations. (1) C6H6 + Br, = C,H,Br,. (2) C,H,Br, + 2ZnEt, = C,H,Et, + ZnBr, And on oxidation with chromic acid Besides the two meta-acids mentioned above, they also obtained benzoic acid, parabromobenzoic acid, and terephthalic acid, but no phthalic or orthobromobenzoic acids.This formation of meta-compounds by direct addition of bromine to benzene is one of great interest, and the fact that no ortho-disub- stitution derivatives seemed to be produced rendered it still more perplexing. We have repeated the work of Ador and Rilliet, and find it to be substantially correct, but as we have been able to prove that ortho-di-derivatives are also produced, and that a different result is obtained when bromine and benzene are allowed to react in the dark or in sunshine, we have thought it worth while to record the facts. The method employed by Ador and Rilliet was briefly the following.Dry benzene (200 grams) was mixed with bromine (6 grams), the mix- ture exposed to sunlight, the product washed with water and a litlle dilute soda, dried, and boiled with zinc ethide. for 20 hours. The ex- cess of benzene mas then distilled off, and all that boiled above 110' was collected and oxidised with chromic acid. Our experiments were made on a somewhat larger scale, in the hopes of obtaining perhaps enough of the ethyl compounds to separate by VOL. LXXlII. It242 NOTE ON TEE ACTION OF BROMINE ON BENZENE. fractional distillation, but this was found to be impossible, as only very small quantities of the substances were produced, and the product consisted of a mixture having no definite boiling point. Our first series of experiments consisted in allowing the dry benzene (which had been carefully prepared from pure crystalline benzene by distillation) and bromine (also purified) to remain i n the dark for 24 hours.From 500 grams of benzene and 50 grams of bromine we obtained only about 7 C.C. of liquid boiling above 100'. I n another experiment with the same amounts, we obtained somewhat more, but the reaction did not seem to have proceeded far, and much bromine remained unacted on. The 7 C.C. of liquid boiled between 100' and 270°, and a t no point were we able to say more passed over than a t any other. The various fractions collected at 100-1 20°, 120-170°, 1 70-210°, and above 210' were separately oxidised with potassium permanganate. The two fractions of lower boiling point gave considerable quan- tities of benzoic acid (m.p. 120°), but mixed with i t were traces of a bromorthophthalic acid, as eosin was formed when it was heated with resorcinol and sulphuric acid. From the fraction 170-210', we were able to isolate an acid containing bromine which melted at 248' ; para- bromobenzoic acid melts at 251'. A determination of bromine gave 39.0 per cent. ; C,H,Br* COOH requires Br = 39.8 per cent. ; the amount of silver in the silver salt was also determined, Found Ag=37.6; C6H,Br*COOAg requires Ag = 35.6 per cent. The amount of acid at our disposal, however, was so exceedingly small (about 0.3 gram) that we were unable to purify it properly, which fact may account for the excess of silver found in the analysis of the salt. From the fraction 210' and above, a very small amount of acid was obtained which was partly soluble in hot water ; it did not give any reaction for an ortho- dicarboxylic acid of benzene when heated with resorcinol and sulphuric acid, it melted at 185', and sublimed at a higher temperature. An analysis gave 39.8 per cent.of bromine, but its melting point does not agree with that of any of the bromobenzoic acids, Our next experiments were made with the same quantities of benz- ene and bromine, which were carefully purified, dried, and mixed a t - 10'; the mixture, after being exposed t o sunlight for 6 hours, was washed with water, dried over calcium chloride, and 40 grams of zinc ethide were then distilled into the dry mixture and the whole boiled for 24 hours (3 days). The product was washed with dilute hydro- chloric acid, dried, and fractionated ; 34 C.C.passed over above loo', this was separated into the following fractions, 100-120' about 5 c.c., 120-150' about 4 c.c., 150-200' about 5 c.c., above 200' about 20 C.C. These fractions were oxidised, as in the preceding case, with potassium permanganate. The first fraction gave large quan-MATTHEWS : BENZENE HEXABROMIDE. 243 tities of benzoic acid, but after evaporating the benzoic acid on the water bath, a residue was left which gave a strong fluorescein reaction with resorcinol and sulphuric acid, proving the presence of an ortho- phthalic acid. The second fraction gave also chiefly benzoic acid, but after this acid had been volatilised at loo', there remained a small amount of an acid which was almost insoluble in cold water; i t was soluble in ether and slightly so in hot water, and was purified by several times dissolving it in alcohol and precipitating with water.It did not contain bromine, and gave no phthalic acid reaction with re- sorcinol. On comparing it with isophthalic acid, it seemed identical under the microscope, both when crystnllised from water and when sublimed. When the two acids were heated, they both behaved in a similar manner, melting and subliming at about 310'. Some of the salts of this acid were compared with those of isophthalic acid; with silver nitrate it gave a white precipitate, with barium chloride a white precipitate, and with ferric chloride a reddish-brown precipitate, identical with corresponding precipitates obtained with iso- phthalic acid.I t s silver salt gave Ag = 57.6 per cent., C,H,(COOAg), requiring Ag = 56.8 per cent, As the only other acid that it could have been was terephthalic, pure terephthalic acid was also compared with i t under the microscope, but the two appeared quite different in crystal- line form. It seems certain, therefore, that Ador and Rilliet's obser- vation was correct, and that when bromine is allowed to react with benzene in sunlight, meta-di-derivatives are formed. The only acid that could be separated from the fraction of highest boiling point was parabromobenzoic acid melting a t 2 5 0 O . It appears, therefore, from these results, that when bromine is allowed to act on benzene in sunlight some dibrom-additive products are formed in very small quantities, which by the reactions employed can he converted into dicarboxylic acids of benzene; as we have ob- tained acids that yield fluorescein and eosin (xhen heated with resor- cinol), parabromobenzoic acid and metaphthalic acid, it follows that bromine is capable of reacting with benzene to form ortho-, meta-, and para-compounds. The explanation of this is difficult, and seems entirely a t variance with the action of bromine on bromohenzene.

ISSN:0368-1645    

DOI:10.1039/CT8987300241

出版商:RSC    

年代:1898

数据来源: RSC

摘要:

MATTHEWS : BENZENE HEXABROMIDE. 243 XX.-Benzene Hexabromide. By FRANCIS EDWARD MATTHEWS, Ph.D. IN the course of work on the halogen hexa-additive compounds of benzene and its derivatives, the author has had occasion to prepare the hexabromide of benzene in considerable quantity. R 2244 hlATTHEtVS : BENZENE HEXABROMIDE. As benzene hexachloride exists in two isomeric forms, the existence of two modifications of the hexabromide was to be expected, but, although carefully looked for, no indication of the second modification was obtained. As the hexabromide prepared by the method described in a former paper (Trans., 1892,61,p. 110) seemed homogeneous, its further investi- gation was abandoneduntil a paper was published by Orndorf and Ho welIs ( A m y . Chem. J., 1896,18, pp.312-319), who succeeded in isolating a very small quantity of a second modification from the hexabromide prepared by the method suggested in my paper, but not from that prepared by other methods. Having a considerable amount of crude material on hand, I once more attempted t o obtain the second modification, but in the course of a series of fractional extractions with chloroform performed on some half-pound of substance, I could find no evidence of the more insoluble modification, as the crystals obtained from the final extract had the same crystalline form, melting point, and solubility as those from earlier portions. I n the method of preparation adopted by Orndorf and Howells there was, however, one slight difference from that which I used, and this may account for the difference in the result.After exposure to sunlight, they evaporated the mixture of bromine, water, and benzene t o dryness, and subsequently made extracts of the residue ; my crude material consisted solely of the solid precipitated during the action of sunlight, which was roughly freed from the mother liquor by filtration through coarse muslin, and by subsequent washing with benzene, so that it seems probable that the second modification, although very insoluble, is produced in such small quantity as not to precipitate spontaneously from the mother liquor, which consists of benzene, a considerable quantity of bromobenzene, and a small amount of para- dibromobenzene. Bromobenzene does not appear t o be capable of forming a hexabro- mide under the conditions in which benzene hexabromide is produced, the bromine displaces hydrogen in the nucleus, and paradi bromobenzene is almost exclusively formed.Bromobenzene also could not be made to form a hexachloride; on mixing bromobenzene with water and passing in chlorine, bromine is liberated, rapidly in sunlight, more slowly in diffused daylight, and on continuing the action a complex mixture of halogen compounds is formed. In all its reactions save one, benzene hexabromide behaves as has been described by previous investigators; the sole difference is the action of alcoholic alkali hydroxides on it. According t o previous work, benzene hexabromide is decomposed by alcoholic solutions ofMATTHEWS : BENZENE HEXABROMTDE. 245 alkalis, similarly to the hexachloride, quantitatively into 1 : 2 : 4 tri bromobenzene with the removal of 3 mols.HBr. This I have found not to be the case, as on boiling the pure recrystallised hem- bromide with alcoholic soda, more bromine is removed than is required by the equation C,H,Br, + 3NaOH = C,H3Br, + 3NaBr + 3H,O. Some pure benzene hexabromide, recrystallised from chloroform, and which gave on analysis 85.44 per cent, of bromine (Theory 86.02) was decomposed with excess of alcoholic soda free from chlorine, and the amount of bromine in solution was determined. 0.2298 gram C,H,Br, gave 0.2707 gram AgBr. Br = 50.1. 0.2154 ,, C,H,Br, ,, 0.2444 ,, AgBr. Br = 48.3. Theory for removal of Br, = 43.0, of Br,= 57.3 per cent. From the above it follows that 1 mol. C,H,Br, parts with about 3& atoms of bromine to alcoholic soda, and, in order to identify the products, the reaction was carried out on a much larger scale.After the hexabromide had been boiled with excess of alcoholic soda for some time and everything had gone into solution, excess of water was added, and the semi-solid precipitate extracted with ether ; the solu- tion was dried, the ether distilled off, and the residue fractionally distilled, when the whole came over between 210' and 280°, two principal fractions being obtained, the first distilling at 220-230°, and the other at 260--270°. Both of these portions solidified on stand- ing, and the fraction 260-270°, after recrystallisation from benzene, gave the following figures on analysis, 0.2820 gave 0.5070 AgBr. Br = 76.5. C,H,Br, requires Br = 76.2 per ct.It was identified as unsymmetrical tribromobenzene from the above figures by its boiling point and melting point (43'). The other chief fraction, 220--230°, was freed from oily matter on a porous plate and recrystallised from benzene, in which it was very soluble, by spontaneous evaporation. It was then found t o melt at 86-87'', and gave the following figures on analysis. 0.1036 gave 0.3094 AgBr. 0.2744 ,, Br = 68.0. 0.3096 CO, and 0.0490 H,O. C = 30.8 ; H = 2.0. C,H:,Br2 requires Br = 67.8 ; C = 30*5 ; H = 1.7 per cent. The substance is therefore a dibromobenzene, and from its melting point and from the melting point of its nitro-derivative (83') it appears to be the para-compound. Between 230' and 260°, small fractions of liquid substances were obtained, but as the small amount precluded their separation by fractional distillation, an attempt was made to 0,1032 9 , 0.1160 CO, ,, 0.0180 H20. C = 30.6 ; H = 1.9.246 SHENSTONE AND EVAh’S : OBSERVATIONS ON THE separate them by fractional crystallisation of their nitro-derivatives ; the presence of orthodibromobenzene was suspected, but the results obtained did not completely substantiate its presence. Tribromobenzene yields no trace of dibromobenzene, neither does it part with bromine when acted on by boiling alcoholic soda; the formation of the dibromobenzene, therefore, takes place during the decomposition of the benzene hexabromide . Benzene hexabromide, on reduction with nascent hydrogen in acid alcoholic solution, yields benzene. The benzene thus obtained was found to yield both modifications of benzene hexachloride on treatment with chlorine. ROYAL INDIAN ENGINEERING COLLEGE, COOPERS HILL.

ISSN:0368-1645    

DOI:10.1039/CT8987300243

出版商:RSC    

年代:1898

数据来源: RSC