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928 ABELL: THE CONDENSATION OF XCVII1.- The Condeizscction of Phenyl Ethyl Ketone and Benxaldeh yde. By ROBERT DUNCOMBE ABELL, B.Sc. (Wales), 1851 Exhibition Scholar of the University College of North Wales, Bangor. ACETOPHENONE condenses with benzaldehyde in three proportions : (i) One mol. of acetophenone with 1 mol. of benzaldehyde, t o form an unsaturated ketone, benzalacetophenone (Claisen and Clapardde, Ber., 1881, 14, 2464 ; Claisen Ber., 1887, 20, 655). c6H,*COoCH3 4- C,$&*CHO = H,O -I- C,H,*CO*CH:CH*C,H,. (ii) Two mols. of acetophenone with 1 mol. of benzaldehyde, to form benzaldiacetophenone or 2-phen yl-l : 3-dibenzoglpropane (Kostanecki and Rossbach, Bey., 1896, 29, 1492). C6H5*CO*CH, CGH5*CO* vH2 O:CH*C,H, = 7H*C,H5 + H,O. C,H5*CO*CH3 C6H5 CO CH, (iii) Three mols.of acetophenone with 2 mols. of benzaldehyde, t o form two stereoisorneric dibenzaltriacetophenones or 2 : 4-diphenpl- 1 : 3 : 5-tribenzoylpentanes (ibid.). C,H,*CO*CH, C,H; ClO*v H, 0: CH*C,H, yH*C,H5 O:C€1~C6H, yH* C6H5 C6H5*CO*CH, = C,K,*CO*yH + 2H20. C6H,*CO*CH, C6H,* CO CH, Ketones of the form R*CO*CH,*R, for example, phenyl ethyl ketone, C6H,*CO*CH2=CH3, do not undergo this third form of condensation. The property of condensation is intimately associated with the group -CO*CH2-, the hydrogen atoms of which are slightly electro- negative in character. The formation of the preceding compounds may be regarded as taking place in the following manner : (i) One rnol. of acetophenone condenses with 1 mol. of benzaldebyde t o form benzalacetophenone. C6H5*CO*CH, + C,H,*CHO - H,O = C,H,*CO*CH:CH*C,H, (ii) One mol.of benzalacetophenone then unites with 1 mol. of a cetophenone to form 2-phenyl-1 : 3-dibenzoylpropane. C,H,-CO*EH C6H,*CO*$!H2 + C6H,~CO*CH, C,H5*C0 *CH, CH*C,H5 = yH*C,HrPHENYL ETHYL KETONE AND BENZALDEHYDE. 929 (iii) One mol. of this 1 : 5-diketone again unites with 1 mol. of benzalacetophenone to form 2 : 4-diphenyl-1 : 3 : 5-tribenzoylpentane. prejent in the acetophenone taking part in these reactions, whereas in the third reaction this group is present in the 1 : 5-diketone. If now phenyl ethyl ketone, C6H,*CO*CH,*CH,, take the place of acetophenone, this substance also contains the group -CO*CH,-, and consequently reactions corresponding to i and ii are to be expected, but not the third reaction, because the 1 : 5-diketone, 2-phenyl-1 : 3-di- methyl-1 : 3-di benzoylpropane, yH*C,H,, which we should expect to be formed in the second reaction, would no longer contain this group.It was therefore expected that benzaldehyde and phenyl ethyl ketone mould condense in two proportions : (i) One mol. of phenyl ethyl ketone with 1 mol. of benzaldehyde to form the unsaturated ketone, benzalpropiophenone, or benzalmethyl- acetophenone : C6H,*CO* yH*CH, C,R5'CO* CH*CH, CGH,*CO*CH2*CH3 -!- C,H,*CHO = H,O + C,H,*CO*R*CH, CH*C,H; (ii) Two mols of phenyl ethyl ketone with 1 mol. of benzaldehyde to C,H,*CO* CH2* CH, C,H,*~O*$!H*CH, C,H,*CO*CH,*CH, C,H,*CO*CH*CH, The following experiments were undertaken with the view of in- Mixtures of phenyl ethyl ketone and form one or more stereoisomeric 1 : 5-diketones, for example : O:CH*C,H, = yH*c6H5 + H,O.vestigating these reactions. benzaldehyde werq treated with the following reagents : Sodium methoxide, 20 per cent. solution. Sodium ethoxide, 20 per cent. solution. Potassium hydroxide in aqueous alcoholic solution. Dry hydrogen chloride.930 ABELL: THE CONDENSATION OF Condensation of Phenyl Ethyl Ketone and Benxcddehyde by means of a 20 per cent. solution of Sodium Methozide. A mixture of 5 grams of benzaldehyde and 6.3 grams of phenyl ethyl ketone was treated with 15 C.C. of a 20 per cent. solution of sodium methoxide. After standing for 7 days, the gelatinous, yellow mass was dissolved by shaking with ether and dilute hydrochloric acid. The ethereal solution was washed with a dilute solution of sodium hydroxide and afterwards with water, and was then dried over fused sodium sulphate.After distilling off the ether, a clear oil remained which was distilled under 25 mm. pressure, until the thermometer rose rapidly to 200'. A fraction boiling at 95-120' consisting of un- changed benzaldehyde and phenyl ethyl ketone was collected separately. As soon as the thermometer registered 200°, the oil distilling over began t o solidify. The distillation was then stopped, the residue in the flask washed out with dry ether, and the ether evaporated off in n current of dry air. The oil which mas thus obtained crystallised almost completely on standing for a few hours in a vacuum over sul- phuric acid. (1) Examination of the CqistaZZine Portion of the Coiodensc6tion Pro- duct.-The crystalline mass was triturated with cold light petroleum which dissolved out an oil leaving behind a mass of fine crystals melt- ing a t 92-96'.This substance, upon repeated recrystallisation from large quantities of boiling light petroleum, to which a few drops of alcohol had been added, separated in needles melting at 98-99'. It is easily soluble in alcohol, benzene, chloroform, acetone, or ether, but only very sparingly so in boiling light petroleum. On analysis : 0.2 gave 0.581 CO, and 0.1345 H,O. C=79*22; H='i*47. 0.2012 ,, 0.5845 CO, ,, 0.1355 H,O. C=79*21 ; H=7*48. C,H,O requires C = 79.33 ; H = 7.44 per cent. Determinations of the molecular weight by the boiling point method 0.2992 dissolved in 29.16 chloroform gave a rise of temperature 0-5192 dissolved in 29.16 chloroform gave a rise of temperature gave the following results : 0.158'. Mol.wt. =238. 0,258'. Mol. wt. =252. Mean =245.-Cl6Hl8O2 has mol. wt. =242. The substance is not acted on by potassium permanganate or brom- ine and is therefore saturated. Further, it cannot contain a ketonic or an aldehydic group because it does not react with phenylhydrazine, hydroxylamine, &c. DiacetyZ Derivative, C,GHl,(O*CO*CH,),.-Two grams of the sub-PHENYL ETHYL KETONE AND BENZALDEHYDE. 931 stance were boiled with 2 grams of fused sodium acetate and 20 grams of acetic anhydride for 4 hours. The oil which first separated on treatment with water rapidly became crystalline and after recrys tal- lisation from alcohol, formed prisms melting at 123-124'.On analysis : 0.2005 gave 0.541. CO, and 0.184 H,O. C = 73.61 ; H = 6.86. 0.202 ,, 0.545 CO, ,, 0.1232 H,O. C = 73.57 ; H = 6.77. C,oH2,04 requires C = 73.62 ; H = 6.74 per cent. The substance, is therefore, the diacetyl derivative of C16HlS02, which is thus proved to contain two hydroxyl groups. Oxidation of Substance C,,H1,02 (m. p. 98-99').-When heated with a mixture of potassium dichromate and sulphuric acid, this sub- stance is oxidised to benzoic and carbonic acids. One gram of the compound was next dissolved in 40 grams of glacial acetic acid and oxidised at the boiling point with 0.6 gram of chromic acid, added in small quantities at a time. The green solution so ob- tained was precipitated with water, and the precipitate extracted with ether.The ethereal solution, after being mashed with sodium hydroxide and then with water, was dried over fused sodium sulphate and the ether evaporated off in a current of dry air. An oil remained which readily crystallised, and after recrystallisation from alcohol was ob- tained in needles melting at 82*5-S4'. On analysis : 0.1717 gave 0.5072 CO, and 0.0922 H,O. C=80*54; H=5.96. 0*2005 ,, 0.5935 CO, ,, 0.108 H,O. C=S0*59 ; H=5*98. C16H1402 requires C = 80.67 ; H = 5.88 per cent. The oxidation product (0.5 gram) being in all probability a ketone o r an aldehyde, was dissolved in alcohol, and mixed with a 50 per cent. solution of hydrazine hydrate (0.3 gram). After standing for 13 hours, the solution was precipitated with water, and the precipitate, after recrystallisation from alcohol, was obtained in glistening plates melting at 222-223'.It was dried a t 120' and analysed : 0,2022 gave 21.7 C.C. nitrogen at 16' and 740 mm. C16H14N2 requires N = 11 -96 per cent. The compound C,,H,,O, (m. p. 825--84O), and the compound CI6Hl4N2 (m. p. 222-2523'), are therefore identical with the methyl- dibenzoylmethane and the 3 : 5-diphenyl-4-methylpyrazole obtained by Beyme (Biss. Leipxig, 1900). From this it follows that the methyl- dibenzoylmethane is obtained from the corresponding 1 : 3-disecondary alcohol, namely, 1 *3-diphenyl-2-methyltrimethylene glycol, for example : N = 12.12. C,H,*FH*OH C6H,*$?0 FH*CH, + 2 0 = YH*CH, + 2H,O. C6H,*CH*OH Cp,H,*CO932 ABELL: THE CONDENSATION OF The methyldibenzoylmethane being a 1 : 3-diketone, reacts with hydrazine to form 3 : 5-diphenyl-4-methylpyrazole, for example : C,H,*YO NH2 CGH5.E- NH FH*CH3 + 1 = 7*CH3 I + 2H,O.C6H5*C0 NH2 CGH,*C=-IIJ The formation of 1 : 3-diphenyl-Z-methyltrimethylene glycol is remarkable, but may be explained on the assumption that the un- saturated benzalpropiophenone is first formed by the condensation of 1 mol. of phenyl ethyl ketone with 1 mol. of benzaldehyde, thus : C6H5*CO*CH,*CH3 + C,H,*CHO = ~6H,*cOwfl*CH3 + H20. CH*C6H5 This unsaturated ketone might then take up a mol. of water to form a saturated ketone-alcohol, the ketonic group being af termards reduced by the sodium methoxide to the corresponding secondary alcoholic group. It is scarcely possible that the reduction of the ketonic group takes place before the elements of water have been taken up by the benzal- propioyhenone to form a saturated compound, because the double bond would in all probability be first attacked by the nascent hydrogen and one or more of the following compounds would be formed : C,H,*CO*CH( CH,) -CH,*C,H,.C6H,*CH(OH)*C(CH3):CH*C6H5. C,H ,*CH(OH)* CH( CH,)*CH, C6H,. none of which has been found in the crystalline part of the product of the original condensation, but may be present in the solution of the oily part in light petroleum. (2) Examination of the Oily Portion of the Condensation Pt*oduct.- The solution of the oil in light petroleum was dried by means of fused sodium sulphate, the solvent distilled off, and the residual oil distilled under reduced pressure. The fraction boiling at 2 10 -2 1 3 O under 23 mm.pressure formed a clear, yellowish oil which furnished the following results upon analysis : 0.2175 gave 0-6742 CO, and 0.1287 H20. These figures do not agree with those required by benzalpropio- phenone, C1,H,,O (C = 86.48 ; H = 6.31 per cent.). The oil, however, has an unsaturated constitution, since it readily absorbs bromine. It is therefore probably benzalpropiophenone con- taining a small quantity of the 1 : 3-disecondary alcohol which boils at about the =me temperature (the pressure being the same in the two cases), or the impurity may consist of small quantities of other pro- C = 84-54 ; H= 6-57, 0.2 ,, 0.621 CO, ,, 0.1197 H20. C-84.68; H=6.65.PHENYL ETHYL KETONE AND BENSALDEHYDE. 933 ducts of the reaction which cannot be separated from the benzalpropio- phenone by distillation.On comparison of the figures with those required by the formuh of the various products which might result from the reaction, it will be seen that they agree most closely with the figures for benzalpropio- phenone. The figures are here given for comparison : C,H,*CO*C(CH,):CH*C,H, requires C = 86.48 ; H = 6.31. c~H,=CH(OH)=C(CR,):CH* C,H, C',H5.C0.CH.(CH,).CH2.C6H~ } 9 9 = 85*73 ; = 7'14* C6H,*CH(OH)*CH(CH3)*CH,*C,H5 ,, C = 84.96 ; H = 7.96. Found (mean) C = 84.61 ; H = 6.61. This conclusion is confirmed by the reaction of benzalpropiophenone with phenyl ethyl ketone described on p. 936. Condensation of P h e n y l EthJ Ketone and BenxuldelLydle 6y means of a 20 pel. cent. solution of Sodium Ethoxide.A mixture of 5 grams of benzaldehyde and 6.2 grams of phenyl ethyl ketone was treated with 15 C.C. of a 20 per cent. solution of sodium ethoxide. After standing for 7 days, the hard, pink-coloured product was shaken up with ether and dilute hydrochloric acid, when a small quantity of a crystalline compound melting at 160-1 63' remained undissolved. This substance, after recry stallisation from alcohol, melted at 162-163'. The ethereal solution was treated in the same way as that obtained from the condensation by means of sodium methoxide and contained : i. Unchanged benzaldehyde and pheayl ethyl ketone. ii. 1 : 3-Diphenyl- 2-methyltrimethylene glycol, C,,H,,O, (m. p. 98-99'), crystallising in needles. iii. A yellowish oil boiling at 810-213O under 23 mm. pressure, This was analysed, with the following results : 0,206 gave 0.6435 CO, and 0.1227 H,O.C = 85.19 ; H = 6.62. 0.206 ,, 0.6415 CO, ,, 0,1242 H,O. C 4 4 . 9 2 ; H= 6.69. C,,H,,O requires C = 86.48 ; I€ = 6.31 per cent. This oil readily absorbs bromine and is consequently slightly impure For further proof of iv. A compound crystallising in small, six-sided crystals melting a t 0.201 benzalpropiophenone as in the preceding case. this conclusion, see p. 935. 163-163', which furnished the following results on analysis : gave 0.621 CO, and 0.1 245 H,O. C = 84.25 ; H = 6.88. 0.2005 ,? 0.619 CO, ,, 0.1235 H,O. C=84.19; H=6*84. C,,H,40, requires C = 84.27 ; H = 6.74 per cent. VOL. LXXIX. 323934 ABELL: THE CONDENSATION OF This substance is obviously 2-phenyl-1 : 3-dimethyl-1 : 3-dibenzoyl- propane, formed by the condensation of 2 mols.of phenyl ethyl ketone and 1 mol. of benzaldehyde with separation of 1 mol. of water (p. 929). To test the coi*rectness of this view, a mixture of 5 grams of benz- aldehyde (1 mol.) and 12.6 grams of phenyl ethyl ketone (2 mols.) was treated with 15 C.C. of a 20 per cent. solution of sodium ethoxide, with the result that the compound C,,H,,O, (m. p. 163-163') was obtained in slightly greater quantity. The preparation of pure benzalpropiophenone was next attempted, potassium hydroxide or hydrogen chloride gas being used as the condensing agent. Condensation, of Pheql EtAyZ Ketone and Benddehyde hy means of Potassium Hydroxide. A mixture of 12.6 grams of phenyl ethyl ketone and 10 grams of benzaldehyde was dissolved in 100 C.C.of alcohol, and 3-4 C.C. of a concentrated aqueous solution of potassium hydroxide were added ; the whole was diluted with water, but not in such quantity as to precipitate the ingredients, and the mixture allowed to stand for 7 days. The aqueous alcoholic solution was precipitated with water and extracted with ether. The ethereal solution, dried by means of fused sodium sulphate, was evaporated, and the remaining oil distilled under 22 mm. pressure and collected in the following fractions : i. Benzaldehyde, b. p. 85-88' (185-190' under atmospheric pressure). ii. Phenyl ethyl ketone, b. p. 103-!08' (210-215O atmospheric pressure). iii. A yellowish unsaturated oil, b. p. 200-220'. The last portion was redistilled a number of times, and the portion boiling at 210-213' under 23 mm.pressure analysed : 0.2175 gave 0.685 GO, and 0,1227 H,O. Benzalpropiophenone can therefore be prepared pure by this method, A small quantity of a yellowish oil separated. C = 86-35 ; H = 6-27, C,,H,,O requires C = 86.48 ; H = 6.31 per cent. but the yield (10 per cent. of the theoretical) is small, Condensation of Phertyl Ethyl IrTtone and Benxaldeiyde by means of lfydrogen Chloride. When n mixture of inoleculnr quantities of phony1 ethyl ketone and benzaldehyde is treated with dry hydrogen chloride until 1 mol. has been absorbed, a dark oil is obtained which readily splits off hydrogen chloride, and from which no definite chlorine compound could bePHENYL ETHYL KETONE AND BENZALDEHYDE. 935 isolated. This oil after being kept for 12 hours in a closed vessel was gently heated on a sand-bath in a current of air until it no longer gave off hydrogen chloride, and was then distilled under reduced pressure.The fraction boiling at 234-235' under 25 mm. pressure, which still contained chlorine, was analysed with the following results : 0.2345 gave 0.69S5 CO, and 0.1275 H,O. 0.232 ,, 0.7267 CO, ,, 0.13 H,O. C=85*43; H=6.22. 0,4632 ,, 0.0239 AgCI. C1=1*27. 0.4947 ,, 0.02714 AgCI. Cl= 1.35. C = S 4 . S ; H= 6-31. CI6HL50Cl requires C = 74.29 ; H = 5.80 ; C1= 13-73 per cent. C,,H,,O ,, C = 86.48 ; H= 6.31 per cent. From these figures it is evident that about nine-tenths of the chlorine has been eliminated by heating, one-tenth still remaining after a number of distillations.It is therefore probable that in the reaction two isomeric compounds are formed, and that one of these is much less stable than the other. The remaining chlorine can be removed as hydrochloric acid by boiling the substance with an aqueous 50 per cent. solution of potassium hydroxide. Benzazpropiophenone so obtained is straw-yellow and distils without decomposition a t 210-213' under 23 mm. pressure ; the yield amounts to '70-80 per cent. of t,he theoretical. It was analysed with the following results : 0,2122 gave 0.6732 CO, and 0.122 H,O. C=86.50; H=6*38. 0.209 ,, 0.6625 CO, ,, 0.119 H,O. C = S6.45 ; H = 6.32. C,,H,,O requires C = 86.48 ; H = 6.31 per cent. On analysis : C = 84.49 ; H = 6.53. The phenylhydrazone, crgstallised from alcohol in yellow needles softening at 115' and melting at 127-128'.0*2012 gave 0.6235 CO, and 0.1 IS5 H,O. 0,2005 ,, 16 C.C. nitrogen a t 20' and 752 mm. N = 9.03, C,,HZoN2 requires C = 84.61 ; H = 6.41 ; N = S.97 per cent. Benzalpropiophenone dibromide, C6H,*CO*CBr(CH,)*CHBr*c6H~. -Ten grams of benzalpropiophenone mere dissolved in SO grams of chloroform, and 7.3 grams of bromine in 20-30 grams of chloroform gradually added t o the solution, , The bromine was rapidly decolorised with a slight development of heat, and only a small quantity of hydrogen bromide was evolved, The product was a t once poured into an evaporating dish, the chloroform evaporated in a current of dry air, and the thick viscid oil placed over sulphuric acid and potassium hydroxide in a vacuum until the weight was constant.The green viscous oil thus obtained did not crystallise even after long standing, or when cooled with a mixture of solid carbonic acid and ether. On analysis : 3 s 2936 ABELL: THE CONDENSATION OF 0.232 gave 0.438 CO, and 0.0797 H,O. C = 50.31 ; H = 3.81. 0.337 ,, 0.3205 AgBr. Br=41-'75. 0.2792 ,, 0.273 AgBr. Br=41-60. C1,H,,OBr, requires C = 50.26 ; H = 3-66 ; Br = 41.89 per cent. I n the various preparations of the dibromide, the amount of bromine 0.2515 ,, 0.4642 CO, ,, 0,0865 H,O. C=50'34; H=3.82. present was found to vary between 38 and 43 per cent. Condensation of Benxalpopiophenone with Phenyl Ethyl Ketone. It seemed probable that for the satisfactory preparation of Z-phenyl- 1 : 3-dimethyl-1 : 3-dibenzoylpropane, the previous formation of the unsaturated benzalpropiophenone is necessary.The following experi- ments were therefore made. A mixture of 4.4 grams of benzalpropiophenone and 2-7 grams of phenyl ethyl ketone was therefore treated with a solution of 0-5 gram of sodium in the least possible quantity of absolute alcohol. The mixture rapidly became pink in colour, with development of heat; crystals soon began to form, and in 48 hours the whole had solidified to a compact, crystalline mass. This was triturated with dilute alcohol, filtered, and washed with alcohol, when a nearly white, crystal- line mass melting at 15S-16Oo was obtained, which after recrystal- lisation from alcohol melted at 162-163'. It was almost insoluble in hot light petroleum, and only sparingly soluble in boiling alcohol and in ether. The yield of 2-phenyl-1 : 3-dimethyl-1 : 3-dibenzoylpropane was almost quantitative. Erom the alcoholic mother liquors, a small quantity of a compound much more soluble in alcohol was obtained.This crystallised in needles and melted a t 121-122'. On analysis : 0*3005 gave 0,6165 GO, and 0.1225 H,O. C = 83.85 ; H = 6.78. 0.2015 ,? 0.6202 CO, ,, 0.123 H,O. C=S3.96 ; H=6*78. C,,H,,O, requires C = 84.27 ; H = 6-74 per cent. As the analyses show, this compound is isomeric with 2-phenyl-1 : 3- dimethyl-1 : 3-dibenzoylpropane (m. p. 162-1 63O). The yield amounts to 1 gram from reactions yielding upwards of 60 grams of the isomeride. The mode of formation of these compounds, more especially of that of the higher melting point, by the above method indicates not only that they are isomeric 1 : 5-diketones, but is also a further proof of the unsaturated constitution of benzalpropiophenone.Similar reactions of unsaturated compounds with substances which contain electro-negative hydrogen atoms have been carried out by Michael (J. p. Chem., 1887, [ii], 35, 349), who studied, amongst otherPBENYL ETHYL KETONE AND BENZALDEHYDE. 937 reactions, the behaviour of ethyl cinnamate with the sodium deriva- tives of ethyl malonate and ethyl acetoacetate. I n the above case also, the union of the unsaturated ketone benzal- propiophenone with phenyl ethyl ketone follows in the sense of Michael's " positive-negative " rule (J. yr. Chern., 18SS, [ii], 37, 522), according to which '' in the union of a sodium compound with an un- saturated compound, the sodium atom, replacing a hydrogen atom of the acid methylene (= CH,) group, links itself to the carbon atom (of the unsaturated compound) which has the strongest negative character," in this case to the carbon atom attached to benxoyl on the one side and to methyl on the other in the radicle, C,H,*CO*S.CH,.Consequently, the reaction may be represented by the following equation : C,H,* C0.E : CH, U,H,.CO*yNa*CH, CH*C,H, - - yH*C,H,. + CGH5-CO*CHNa*CH, CGH,*CO*CH*CH, The sodium compound so formed is then probably decomposed by the alcohol with regeneration of sodium ethoxide. I n carrying out this reaction, it is necessary to use an amount of sodium in agreement with the above equation in order to obtain the best results, and under these conditions the yield of 1 : 5-diketone is almost quantitative.Again, in this reaction it was found that methyl alcohol cannot take the place of ethyl alcohol. This explains how it is that the 1 :5-diketone is formed when phenyl ethyl ketone and benzaldehyde are condensed by means of sodium ethoxide, and not when sodium methoxide is used. As this reaction is practically quantitative, i t can be used t o ascer- tain whether the oils boiling a t 210-213' under 23 mm. pressure, obtained by the condensation of phenyl ethyl ketone and benzaldehyde by means of sodium methoxide and sodium ethoxide respectively, con- sist of benzalpropiophenone, as previously concluded. 2.2 grams of each of these oils were mixed with 1.3 grams of phenyl ethyl ketone and treated with 0.23 gram of sodium dissolved in abso- lute alcohol. The yield of 1 : 5-diketone was 3.3 grams, instead of 3.5 grams, that is 94 per cent.of the calculated amount in both cases, thus furnishing conclusive evidence that these oils are almost pure benzalpropiophenone. I n order to investigate further the structure of the isomerides, C25H240,, the reaction with ammonia and with hydroxylamine was studied in the hope of obtaining one and the same pyridine derivative by means of the following reaction : CH,*y H* CO*CGH, C H,* T-=q'C,H, CH,*CH* CO*C,H, C H 3 * C E C .C,H5 CGH5.7 tI + NH, = 2H,O + C,H,*FH TH938 CONDENSATION OF PHENYL ETHYL KETONE. Action of Awmonia o n P~eiz?lk~imet?~?/ZdibePl.no~~~oz)ccne, m. p. 162-1 63'. -One gram of the compound (m. p. 162-163') and 5 C.C.of a saturated alcoholic solution of ammonia were heated in a sealed tube to 200' for 8 hours. Upon opening the tube, in which there was scarcely any pressure, a n oil remained. The contents of the tube were dissolved in alcohol and allowed t o evaporate in a vacuum over sulphuric acid. A small quan- tity of a pink compound melting a t 155-156O was obtained, along with a large quantity of resinous matter. After numerous recrystal- lisations from alcohol, the former was obtained in colourless needles melting a t 155-156', and was analysed, with the following results: 0.2149 gave 8 C.C. nitrogen a t 15' and 759 mm. N=4*35, C,SH,3N requires N=4.16 per cent. C,,H,,N ,, N=4.18 ,, From the nitrogen found, this compound may be triphenyldimethyl- dihydropyridine, C,,H,,N, or triphenyldimethylpyridine, C,,H,,N, Considering the large amount of resin formed, it is possible that the same changes have gone on as were observed by Michael (Ber., 1885, 18, 2021) in the formation of ay-lutidine-P-carboxylic ester from aceto- acetic ester, acetaldehyde, and aldehydeammonia.A similar case was observed by Knoevenagel and Weissgerber (Ber., 1893, 26, 436) in the formation of pentaphenylpyridine from benzamarone and ammonia. There is, therefore, not merely a separation of water to form a hydro- pyridine derivative, but possibly a simultaneous oxidation of the hydro- pyridine ring with formation of 2 : 4 : 6-triphenyl-3 : 5-dimethylpyridine. This assumption is justified by the fact that the same compound is obtained by the action of hydroxylamine hydrochloride.Action of Hydvox?/Zamine Hydrochloride on P~enyldimethykdienxoyl- propane (m.p. 162-1 63°).-Twogramsof the substance (m. p. 162-163"), 1 gram of hydroxylamine hydrochloride, and 40 C.C. of 90 per cent. alcohol were heated in a sealed tube at 120-130' for 6 hours. The contents of the tube were precipitated with water and extracted with ether. The ethereal solution left, on evaporation, a pink, crystalline mass, which, aher many recrystallisations from alcohol, separated in colourless needles melting at 155-156'. The yield was 70 per cent. of the theoretical. On analysis : 0.201'7 gave 0,6622 CO, and 0.11s H,O. 0.223 ,, 8.6 C.C. nitrogen at 13' and 744 mm. N = 4.52. C=89*52; H=6.49, Ot2012 ,, 0.66 CO, ,, 0.116 H,O. C=89*44; H=6*40. C&H2,N requires C = 89.02 ; H = 6*S2 ; N = 4-16 per cent.C,,H,,N ,, C = 89-55 ; H = 6.2'7 ; N =4*1S ,, From the analyses, it is obvious that the compound has the formula C,,H,,N, hence hydroxylamine reacts smoothly with formation of 2 : 4 : 6-triphenyl-3 : 5-dimethylpyridine, thus :SODEAU: THE DECOMPOSITION OF CHLORATES. PART 1V. 93'3 CH,* $!H* CO* C6H5 CH,*Y=Y*C,H, CH,* CH*CO*C,H, CH,*C-C*CC,H, Action, of H y d r o q l a n h ~ Hydrochtode on Pheizylclinteth~ Zdibenxoyl- propane (m. p. 121-122°).-The isomeride (m. p. 121-122") was not treated with ammonia on account; of the very limited quantity obtain- able, 0.4 gram of the substance, 0.5 gram of hydroxylamine hydrochloride, and 10 C.C. of 90 per cent, alcohol were heated in a sealed tube a t 120-130' for 4 hours, and the product precipitated with water and extracted with ether, Upon evaporation, the ethereal solution de- posited a residue of pink crystals, which, af ter many recrystallisations, were obtained as colourless needles melting a t 155-156'. On analysis: 0.18 gave 6.8 C.C. nitrogen at 15' and 752 mm. C,5H,,N requires N = 4.18 per cent. This compound is identical in appearance and properties with that obtained from the isomeride melting a t 162-163' by means of am- monia and of hydroxylamine. The two substances have, therefore, the same structure, and are 1 : 5-diketones of the formula CGH,*yH 4- OH*NH, = 3IJ,O + C,H,*E 8 N= 4.37. CH,* TH*CO*C,H, C],H,*F]H 3 CH,*CH-CO*C6H, It is hoped that the substances mentioned in this paper mill form but their isomerism is to be explained upon stereochemical grounds. the subject of a future communication. The author wishes to express his indebtedness to Prof. J. Wislicenus for suggesting the above investigation, and for the privilege of being nllomed to pursue it in his laboratory. EI:STES CIIEMISCHES LAEOI~ATORIUM, UNIVEKSITAT, LEIPZIG.

ISSN:0368-1645    

DOI:10.1039/CT9017900928

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

SODEAU: THE DECOMPOSITION OF CHLORATES. PART 1V. 93'3 XCIX.-Thc Decomposition of Chlomtes. Pcwt I V. The Supposed Meclzanical FacilitatioiL of the De- composit'ion of Pot Q s s i z m CWomte. By WILLIAM H. SODEAU, B.Sc. VERY many substances are known to facilitate the decomposition of potassium chlorate, and it has from time to time been suggested that the whole or part of their action is analogous to that of sand, &c., in940 SODEAU: THE DECOMPOSITION OF CHLORATES. PART IV. promoting the boiling of water. The supposed analogy mould, how- ever, appear t o be false, it haviog been shown that the ease of decom- position is not appreciably altered by reducing the pressure to 1 mm. (Trans., 1900, 77, 144). It is dificult to understand why an irre- versible decomposition should be facilitated by the presence of solid particles if these are chemically inert.Were the action purely mechanical, it would presumably be common to all finely divided sub- stances, irrespective of their chemical nature, but several workers have stated that zinc oxide, magnesia,-&c., produce no facilitation. There would seem to be a possibility of chemical action in the case of all substances known to facilitate decomposition of the chlorate. For example, the oxides of manganese, iron, cobalt, nickel, and copper cause the oxygen to be very readily evolved, but in each case the exist- ence of an unstable higher oxide is known or indicated. Platinum black is said to have some facilitating action, n’ot, however, comparable with that of the oxides of manganese, &c., but at the temperatures at which this occurs its chemical activity towards oxygen would appear to be considerable.Mond, Ramsay, and Shields (Phi!. I\*cc?zs., 1895, [A], 186, 689; 1893, 199, 153) have shown that after heating a t 444” in an atmosphere of oxygen, platinum black contains about 66 times its volume of that gas, and that under similar conditions platinous oxide retains more than a quarter of its oxygen even after many hours’ heating. As reduction of pressure mas found to diminish these pro- portions, it would seem that the formation add decomposition of an oxide were probably proceeding simultaneously, hence platinum black cannot well be regarded as chemically inert. References to sand, &c., are discordant, possibly owing to variability of composition.Veley (Phil. Tv-am., 1888, [A], 179, 270) maint.ains that c L finely divided chemically inert particles ” produce acceleration of the de- composition of potassium chlorate, but publishes only one experiment t o establish this, and cites no evidence in support of his assumption that the added substance (barium sulphate) was chemically inert. The table referring to this experiment appears to indicate that the presence of 1 per cent. of barium sulphate increases the rate of de- composition to the average extent of 500 per cent,, but a statement in the text * shows that before systematic observa.tians were taken the average increase amounted only to about 100 per cent. Veley also shows that a similar proportion of manganese peroxide produces a far greater effect. In the series of experiments describcd in the present paper (see Table, p. 942), both range and rate of decomposition, and therefore the range of temperature, have been varied in either direction, as corn- * “ 104 c.c. of gas were given off from the chlorate containing the barium sulphate, but only 51.2 C.C. from that without the sulphate.”SODEAU: THE DECOMPOSITION OF CHLORATES. PART W. 941 pared with Veley's experiment, but the average increase of rate for the presence of 1 per cent, of barium sulphate amounts t o only 16 pel. cent. This is practically negligible, compared with the influence of many other substances, and seems fully explicable by the fact that double decomposition takes place (p. 943) with formation of a small amount of barium ohlorate, a substance less stable than potassium chlorate.With 1 per cent. of barium sulphate, the decomposition is very slow a t 450°, whilst with 1 per cent. of the peroxide of manganese which is precipitated from the acetate by bromine, the action becomes violent a t about 340'. The author is of opinion that the supposed ability of chemi- cally inert solid particles to facilitate the decomposition of potassium chlorate is unsupported by experimental evidence, and, if existing, is inadequate to explain even a small fraction of the great facilitation produced by the oxides of manganese, iron, cobalt, nickel, and copper, The action of the latter substances, now engaging his attention, would therefore appear to be entirely chemical. EXPERIMENTAL. Two specimens of barium sulphate mere prepared by precipitating solutions of recrystallised barium chloride with excess of " pure " sul- phuric acid, the products being very thoroughly washed by decanta- tion, and dried under reduced pressure, A temperature of 200" was employed in drying the first specimen, but that used in experiment 152 was not previously heated above 100'.Equal weights of carefully recrystallised potassium chlorate, with and without the addition of 1 per cent. of barium sulphate, mere de- composed in similar receptacles placed side by side in a bath of melted pewter, together with a thermometer. The evolved oxygen was collected over water in graduated tubes, readings being taken at intervals of 2 to 10 minutes, and the loss of weight was determined at the conclusion, in order to guard against the possibility of a leak.The table summarises the results of all such experiments, together with those of the experiment recorded by Veley (Zoc. cit.) ; the num- bers given in the latter case were calculated on the assumption that he measured the gas a t about 20° and 760 mm., but the main issue would not be affected even if the actual temperature and pressure were widely different from these. All numbers were calculated directly from the gas volumes, and the heating was always continuous, although the earlier and later stages are in most cases given separately. The weight of each portion of chlorate was 1 gram in experiment 143, 10 grams in experiment 144, and 5 grams in each of the subsequent experiments. Tubes closed a one end were used in942 SODEAU: THE DECOMPOSITION OF CIILORATES.PART IV 143 144 147 148 149 150 151 152 Vcley 's (ZOC. cit.) { 1<c'10, nlo11e. -____ Range of de. coniposition (total o= 100). 0-20.3 !0*3 -61.1 0- 3'44 3.44- 9.6 0- 1'39 1.39- 4'24 0- 1.07 1.07- 5.94 0- 3-66 0- 3-37 0- 0.35 0.35- 4.33 0- 0.34 0.34- 2-06 0- 0'32 0'32- 2-13 Percentage of total 0 per minute. 0.5s 0.66 0.041 0,034 0*0084 0 *030 0.0071 0.0325 0 '01 52 0.0087 { 0'0024 0'0306 0'0024 0-0107 0.0023 0-0113 0- 0'25 1 0.25- 0'41 i 0*0010 RC10, nlld 1 per cent. of IhSO,. Range of de- composition (total o= 100). 0-25.1 !5*1 -02 0 0- 4'08 4 '08-1 0'6 0- 5.56 5 -56-1 4 -5 0- 1-47 1.47- 8'21 0- 4'20 0- 3-27 0- 2.54 0- 0'54 0.54- 4'46 0- 0.40 0.40- 2.42 0- 0'45 0.45- 2-58 0- 0.51 0.51- 1.48 I Ratio of , rates.Percent age Mixture -__ of total 1 I(C10,' 0 prr minute. 0 72 0 '61 0.049 0.036 0'034 0.094 0 *0098 0.045 0'0175 0.0085 0,0066 0.0037 0'0301 0-0028 0-0126 0-0032 0.0133 '1 0,0116 1.23 0.92 1.18 1-05 (4'00) (3.19) 1-38 1.38 1.15 0-97 0 '75 1.5 0 -98 1-19 1-17 1-40 1-18 \ 2'03 ~ 6'06 experiment 143, but submerged bulbs were employed in the other experiments ; continual interchange must have eliminated from the average any possible difference due to individual bulb tubes, or to position in the bath.* Two bulbs containing the mixture were employed in experiment 150; both chlorate and mixture were duplicated in experiment 152. I n some experiments, potassium chlorate mixed with 5 per cent. of potassium sulphate was placed in an additional bulb tube; the potassium sulphate did not appear to have much influence upon the rate of decomposition, but this proportion dissolves in the fused chlorate.In experiment 147, the behaviour of the pure chlorate was normal, as was shown by the readings of the thermometer and of the volumes of gas evolved from a comparison mixture of chlorate and sulphate of potassium (5 per cent.), but the portion of chlorate mixed with 1 * Veley employed two retorts, each containing 70 grams of potassium chlornte, r t placed side by side in a small square air-bath" which was " packed with asbestos, to distribute the heat of the lamp as uiiiforinly as possible."STERN: THE NUTRITION OF YEAST. PART 111. 943 per cent. of barium sulphate gave results a t variance with every other experiment.It seems practically certain that a trace of some impurity must have been introduced, for the subsequent experiments would appear to have excluded every other explanation ; experiment 148 mas all but identical as regards known conditions, yet it exhibited no such abnormality. Omitting experiment 147, the average increase of rate for tlhe presence of 1 per cent. of barium sulphate amounted to 16 per cent. (ratio of rates = 1 :1*16), a result entirely a t variance with that obtained by Veley. Barium sulphate was found to completely dissolve in 500 times its weight of fused potassium chlorate contained in a test-tube placed in a bath of fused potassium nitrate a t about 480°, and the ‘‘ solution ” gave a thick precipitate on adding fused potassium chlorate containing potassium sulphate. It is evident that (as on adding barium chlor- ide, Trans., 1500, 77, 146) double decomposition takes place, and that in the present instance barium chlorate and potassium sulphate must be formed. The latter substance does not retard the decomposition of potassium chlorate, consequently the production of barium chlorate, a substance less stable than potassium chlorate, would seem to fully account for the trifling facilitation produced by barium sulphate. When 1 per cent. of barium sulphate is added, the amount rapidly transformed into chlorate must be about a fifth of the whole, EXPLOSIVES COMMITTEE’S LABORATORY, ROYAL ARSENAL, WOOLJVICH.

ISSN:0368-1645    

DOI:10.1039/CT9017900939

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

STERN: THE NUTRITION OF YEAST. PART 111. 943 C.-Yhe Nutrition of ITeast. Pm*t IIL By ARTHUR L. STERN, D.Sc. THE work described in the two preceding parts (Trans., 1899, 75, 202 ; J. Peed. Inst. Brewing, 1899, 399) mas continued with the object of obtaining a knowledge of the effect which conditions other than those already discussed had on the growth of yeast, its composition, and the relations of these t o the progress of the fermentation. The experimental method has already been described in Part I ; briefly, i t is as follows. Into a flask holding rather more than a litre are introduced 500 C.C. of a solution of dextrose (&glucose) of definite strength, 1.5 grams of crgstallised asparagine, 0.5 gram of potassium phosphate, 0.2 gram of magnesium suIphate, and 0.02 gram of calcium sulphate.The neck of the flask is closed with a cotton wool plug, and the contents are boiled for 10 minutes. When cool, the yeast is added.944 STZRN: THE NUTRITION OF YEAST. PART This was obtained in the manner described in Part I from the same culture of Burton yeast then prepared. The sugar solution when thus seeded was kept at a constant tem- perature until the conclusion of the experiment. The yeast was then removed by filtration, dried a t 100' until constant, and the nitrogen contained in it estimated. The optical activity of the fermented solu- tion indicated the amount of sugar remaining unfermented. No difficulty mas experienced in filtering 08 the yeast, except when the fermentation was still proceeding. In these experiments, the addi- tion of 0.5 gram of salicylic acid dissolved in 10 C.C.of alcohol t o the 500 C.C. of fermenting solution a t once stopped the fermentation, and the yeast could be easily removed. (1) The InJEuence of Concentrution.-J. Archleb (Zeit. Spiriturrind., 11, 243), using maltose solutions varying in concentration between 1 and 25 per cent., found t h a t as the Concentration of the sugar was in- creased, (a) from 1 to 5 per cent., the weight of yeast obtained increased; ( b ) from 5 t o 10 per cent,, the weight of yeast crop in- creased but slightly; ( c ) from 10 to 14 per cent., the weight of yeast crop increased rapidly; (d) from 14 t5 19 per cent., the weight of the yeast crop diminished; (e) from 19 to 25 per cent., the weight of the yeast crop again increased.These experiments indicate that the weight of the yeast crop varies irregularly as the concentration of the sugar is increased. Experiments were made according to the method described above t o obtain further information on this point. They were performed at 2 5 O , and the amount of seeding was 1.5 cells per 1/4000 cub. mm. The results are given in Tables l a and l b (p. 945). The only differ- ence in the conditions of the two series of experiments is that those of Table l b were performed with 0.75 gram of asparagine per 500 C.C. of solution instead of 1.5 grams used in all the other experiments. As the standard time of fermentation (7 days) allowed in the earlier experiments was found to be insufficient when fermenting solutions containing more than 15 per cent.of dextrose, experiments with these solutions mere repeated, allowing a longer time for fermentation. Curve 1 (p. 946) was drawn by joining the points obtained by taking as abscissae the weights of nitrogen contained in the yeast, and as ordin- ates the concentration of the sugar at the commencement of the fer- mentation ; it clearly shows that as the concentration rises from zero the amount of nitrogen assimilated increases rapidly at first, then more slowly, until with concentrations of more than 15 per cent. the in- crease appears almost to cease ; there is, however, much difficulty in com- pleting the fermentation with concentratious exceeding 20 per cent. The percentage of nitrogen in the yeast does not greatly vary, but is highest with the weakest and strongest solutions here employed.STERN: THE NUTRITION OF YEAST, PART IIJ.985 Duration of fermen ta- tion. Duration of fermenta- tion. Percentage of dextrose before fermen ta- tion. 0 1 3 5 7.5 10 12.5 15 20 25 30 12.5 15.0 17'5 20.0 22.5 TABLE l a . Weight of nitrogeii in yeast crop. Gram per 100 C.C. 0 0028 0*0081 0.0129 0.0178 0.0200 0.0216 0'0246 0.0275 0.0167 0.0148 0.0122 0.0230 0.0238 0.0232 0*0252 0.0253 Percentage of nitrogen in yeast crop. 7.0 8'6 7'8 7'9 7 -1 6.9 7.0 7-2 6.7 7 .O 7 -7 7'4 7.3 7.6 7.8 7 'ti TABLE 16. Percentage of dextrose before fermenta- tion. -~ _____~ 0 1 3 5 7.5 10 1 2 5 15 20 Weight of nitrogen in yeast. Gram per 100 c.c. Percentage of nitrogen in yeast. 0.0028 0-0076 0.0122 0'0165 0'0194 0.0212 0'0236 0.0199 0'0190 0'0160 0'0129 7.0 9-0 7 *4 7'4 6'6 6'6 6-6 6.8 6.5 7 - 1 7'4 Percentage of dextrose inferm en ted, - 0 1 *5 2 '8 3.1 4.2 6.0 6.6 37'4 51.5 65'2 - 5.3 5 '1 5.4 6'6 10.5 Weight of yeast crop.Gram per 100 C.C. 0.040 0'094 0.166 0.226 0.280 0.314 0-352 0.382 0.24E' 0.211 0'160 0.311 0.326 0.306 0-322 0.320 Percentage of sugar nnfermented. - 4 *7 1-8 1.9 2.2 5-8 5'0 12'6 34'5 50.4 62 0 Weight of yeast. Gram per 1co C.C. 0-040 0.085 0.165 0'221 0'293 0'323 0.361 0-291 0293 0.224 0-175 No yeast growth was obtained when no sugar was present. (2.) In,uence of Temperature.-R. Pedersen (Carlsberg Lab. Reports, 1878, 22) found that the yeast cells increase in number most rapidly at 2S0, but that the same total number was produced at 13.5' as a t 23", and that no growth took place at 38O.The experiments summarised in Table 2 were all carried out with946 STERN: THE NUTRITION OF YEAST. PART 111. 10 per cent. dextrose solutions, and the inorganic and nitrogenous nutriment stated above at the temperatures noted. The amount of seed yeast was the same as before, I n order that the fermentations I'crcentage of s u p r before femm&tion. could be completed, the time of fermentation had to be considerably longer at the lower temperatures. These results indicate that at temperatures between 12' and 35" there is little difference in the weight of yeast, and the amount ofSTERN: THE NUTRITION OF YEAST. PART 111. 947 Temperature. nitrogen contained by it, but that a t 30° and above there is a decrease of these factors, and at 37" i t is evident that the functions of the yeast are seriously weakened.Duration of ferments- tion. TABLE 2. 21 25 30 37 9 > Y 7 I Y 5 2 ) 3 Y Y 12" 13 days 15.5 1 16 ), 18 1'2 Y Y Weiglit of nitrogen in yeast crop. Gram pcr 100 C.C. 0.0194 0'0198 0.0221 0'0224 0.0212 0'0173 0.0085 Percentage of nitrogen in yeast crop. 7.7 6.8 6% 6.6 6 -9 7 . 2 7.8 Percent age of sugar unfermented. 14-7 3'6 4.7 9'2 4'4 5 . 6 40.1% Weiglit of yeast crop. Gram per 100 C.C. 0.252 0.291 0-337 0-339 0.310 0.243 0.110 * Six days' fermentation produced but a slight increase in the amount of sugar fermented 2nd a decrease i n the weight of yeast. (3.) The Efect of Vuwjing the Amount of Seed Yeast.-A. J. Brown (Trans., 1892,61, 369) has shown that for any one fermentable solution there is a constant number of yeast cells up to which the yeast will increase if the solution be seeded with a smaller number, and that if it be seeded with a larger number no increase in the number of cells will take place. The experiments summarised in Table 3 were made more particularly t o ascertain the relationship between the weight of nitrogen contained in the seed yeast and that contained in the final yeast crop at the conclusion of the fermentation. They were carried out a t 2 5 O with the quantities of nitrogenous and inorganic nutriment given above, but in view of the great importance of the results three series of experi- ments were made with 5, 10, and 15 per cent.dextrose solutions. On comparing the figures obtained by subtracting the weight of nitrogen added in the seed yeast from that contained in the yeast crop, it is found (except where the seeding is less than 5 per cent.of the crop) that within the limits of experimental error the figures are the same for any one solution, and that, as might be expected from the previous experiments on the effect of concentration, the average for the 5 per cent. solutions is the least, and that for the 15 per cent. solution the greatest. Jn the experiments where the seeding was less than 5 per cent. of thc crop, these differences are below the average. As the percentage of nitrogen contained in the yeast does not vary very materially, these results may be taken as also applying to the94s STERN: THE NUTRITION O F YEAST. PART 111. Weight of nitrogen in tlto I TABLE 3. Difference between the values in the first two columns.Gram per Gram per 100 C.C. ( a ) Five per cent. sugar solutions : 0.0121 0.0144 0'0151 0.0167 0.0176 0-0179 0.0236 0 -0005 0-0006 0'0014 0'0019 0'0040 0.0056 0'0112 Mean., , , , , . ( b ) Ten per cent. sugar solutions : 0.0143 0.0155 0'0161 0-0196 0'0204 0'0218 0.0217 0'0247 0'0269 0.0308 0.0352 0.0002 0'0006 0*0008 0'0017 0 -0023 0-0045 0 0050 0-0066 0'0096 0'0125 0-0172 Mean ........ (c) Fifteen ~ e r cent. solutions : 0.0173 0'0201 0'021 4 0'0248 0'0228 0.0318 0.0009 0*0013 0.0027 0*0040 0.0072 0.0135 I Mean.. , .... 0-0116 0.0138 0.0137 0.0148 0'0136 0.0123 0'0124 0.0132 0-0141 0'0149 0'0153 0.0179 0 0181 0.01 73 0*0167 0-0181 0-0173 0.0183 0.0180 0.0177" 0.0164 0'0188 0.0187 0.0208 0.0156 0'0183 0'0181 Percentage of nitrogen in the yeast.6 .t3 7-1 6.7 7'4 7'3 7'3 7.7 6-9 7.0 6.8 7 '1 6'6 6 -5 5.1 6 -5 7 '0 6.6 7 '1 7 - 1 6-3 7.0 6 '1 6 -7 6 '6 * Mean of the last eight values. Percentage of sugar unfermented. 2.8 1'9 1'1 1 '9 2 *8 2'8 3'4 3 '0 2'0 11 *3 5.1 6'2 2.8 3'0 3 '3 3'0 2.3 3'0 5 .O 9.5 3 9 6'3 4'6 3.9 weight of the yeast, and except when the seeding is very small, a general statement of the result may be made as follows. If t o equalSTERN: THE NUTRITION O F PEAST. PART 111. 949 volumes of any one fermentable solution quantities of yeast u, b, c be added, the resultant crop of yeast a t the end of the fermentation will be a + p , b + p , c +p, where p is a constant quantity dependent on the composition of the solution. If the seeding is very large, this statement must be modified, as yeast always contains some dead or weak cells, and the decomposition of these would introduce more yeast nutriment into the solution. (4) Efect of Time.-It is generally stated that most of the yeast is formed during the early stages of the fermentation and that in the later stages there is little, if any, increase of yeast (Mohr, Wochen- schr.B~azc., 1S96, 3, 210; F. Schonfeld, ibid., 421 ; Delbruck, Bied. Centy., 1880, 217 ; Boulanger, Ann. Inst. Pastew, 1896, 10, 598). To determine the relation of the weight and nitrogen contents of the yeast to the amount of sugar fermented at successive time inter- vals, experiments were performed a t 25' with 10 per cent. dextrose solutions, and the amounts of nitrogenous and inorganic nutriment already noted; the results are given in Table 4 (p.950). The amount of seed yeast in the four series of experiments a, b, c, and d was in the proportions of 1, 3, 9, and 14. Curve 2 (p. 951) was drawn by joining the points obtained by taking as abscissze the weight of nitrogen in the yeast, and as ordinates the corresponding amount of sugar fermented. I t clearly shows that the increase of the yeast, and of the weight of nitrogen contained in it, goes on to the end of the fermentation. After a certain time, which is least in series c, the curve becomes a straight line; that is, the ratio of the amount of sugar fermented t o the weight of nitrogen remains constant during the remainder of the fermentation. The curves show that before constancy is reached, the nitrogen increases more rapidly than the amount of sugar fermented, when the seeding is less than in c (compare cb and 6), and less rapidly when it is greater than in c (compare d).As the percentage of nitrogen in the yeast does not vary much throughout the fermentation, these statements are practically also true for the ratio of the weight of yeast to the weight of sugar fermented. The experiments described in this investigation were primarily made with the object of obtaining a knowledge of the effect of different conditions on the growth of the yeast and its composition, and the relation of these to the progress of the fermentation. As it was necessary to work under conditions which could at any time be exactly reproduced, the choice of yeast foods was restricted to such as could be obtained pure in reasonable quantity.It is known that when employing such yeast foods as are contained in malt worts, yeast water, &c., larger and more nitrogenous yeast crops are obtained. It is thus possible that the results here obtained may be in some VOL. LXXIX. 3 T950 STERN: THE NUTRITION OF YEAST, PART 111. respects abnormal. the future, The author hopes to investigate this question in TABLE 4. Time. Series a : 0 2 days 4 9 ) 6 Y Y lo ) I Series b : 0 1 day 2 Y Y 3 ? t 4 3 3 5 Y Y 7 3 9 Series c : 0 1 day 2 9 9 3 $ 3 5 > 9 Series d ; 0 14 hours 38 9 Y 86 9 s ~~ Weight of nitrogen in yeast. Gram per 100 C.O. 0~0009 0'0045 0'0095 0'0116 0.0138 0-0026 0.0120 0*0150 0*0180 0-0191 0'0205 0-0212 0.0078 0.0123 0.0178 0'0220 0.0249 0.0125 0.0157 0.0259 0-0340 Percentagc of nitrogen in yeast.7.5 7'2 6.5 6 * 0 6.2 7.0 8.0 7 '0 7-0 6.9 6.9 6.9 7.1 6.6 6 *1 6 '1 6.1 6'1 6 '8 6'2 6'2 Percentage of sngar un- fermented. 100.0 90.9 66.0 38.9 6 '0 100.0 75.6 50.8 30.8 18.6 8-4 4-4 100.0 77 *6 49 '3 25 -1 5-4 100*0 75'6 32.0 3.5 Weight of yeast. Gram per 100 C.C. 0.012 0.065 0.147 0.193 0.223 0,037 0,161 0.217 0.260 0'279 0,296 0.310 0.110 0.185 0.290 0.364 0-406 0.206 0.229 0'419 0.548 The results here obtained may be summarised as follows : 1. Any increase of nitrogenous or inorganic nutriment beyond a definite limit will not increase either the amount of nitrogen assimi- lated by the yeast or the weight of the yeast. This limit is but little greater than the largest amount which the yeast is able to assimilate under the conditions of the experiment (Part I, Zoc.cit.). 2. An increase of the sugar is accompanied by an increase in the weight of nitrogen assimilated and in the weight of the yeast, This increase continues up to the strongest concentrations which can be completely fermented. The rate of increase is greatest at the lowest cnncentrations and falls off gradually as the concentration rises.STERN: THE NUTRITION OF YEAST. PART 111. 951 j 20 CURVE 2 (TABLE 4). I- / 2’ 40 60 so Percentayc of sicgas* fermented. 7 r“ 100 3. Temperatares between 1 2 O and 25’ have lout little influence on the weight of nitrogen assimilated and the weight of the yeast crop. A t higher temperatures, reproduction is weakened. 4. The total weight and nitrogen content of the yeast crop obtained at the completion of fermentation are dependent solely on the weight 3 ~ 2952 STERN: THE NUTRITION OF YEAST, PART 111.and nitrogen content of the yeast added to produce fermentation and on the composition of the fermentable solution. 5. During a portion of the fermentation the growth of yeast is pro- portional t o the amount of sugar fermented, and proceeds as long as any sugar remains unfermented. Although the chief object of this work was to obtain these results, yet it was thought that when obtained they would throw additional light on the mechanism of fermentation and yeast growth ; that they do so will be seen from the following. Statements 1 and 2 show that there must be a great difference between the functions of the nitrogenous and inorganic nutriment, on the one hand, and of the eugar on the other; whilst the function of the first two is to supply the necessary material to form the yeast, that of the sugar is twofold-to supply the yeast with material and with, energ y.The chemical products of the decomposition of the sugar (alcohol and carbon dioxide) are useless t o the yeast, and when present in sufficient quantity even deleterious t o i t ; this decomposition of the sugar, however, sets free an amount of energy which has been cal- culated as from 33 to 67 K ; the heat developed has been measured, and amounts to 23.5 R according to Bouffard (Compt. ?*end, 1895, 121, 357), and to 21.4 K according to A. J. Brown (J. Fed. Inst. Brewing, It has been previously suggested by A.J. Brown (Trans,, 1894, 59, 911), by Reynolds Green (Ir’ewuentation, p. 334), and others that the need for this energy is the reason for the fermentation of the sugar, part of i t being employed to carry on the vital actions of the yeast, and part to raise the temperature of the solution, a temperature slightly above the ordinary being most favourable to the yeast. It is a much debated question whether the fermentation of the sugar is the work of an enzyme or of the vital functions of the yeast. Buchner (Ber., 1897, 30, 117, 1110, 2668; 1898, 31, 209, 568, 1084, 1090, 1531 ; 1899, 32, 127), Abeles (Ber., 1898, 31, 2261), and others state that they have isolated this ferment from yeast ; this explanation of their experiments has, however, been combated by Mscfadyen, Morris, and Rowland (Proc.Rog. Soc., 1900, 6’7, 250) and Wrdblewski (Centy. Phyiol., 1899, 22). The great difficulty attending the investigation of the fermentative function of yeast has been to eliminate disturbances due to change in the fermentative power of the plant-that is, to change in the amount of fermentative enzyme, supposing such to be present. Dumas (Ann. Chint. Phys., 1874, [v], 3, S l ) and A. J. Brown (Trans., 1892,61, 369) employed such an excess of yeast as was shown by the latter to result in fermentation without any numerical increase of yeast, and found 1901, 7, 93).STERN: THE NUTRITION OF YEAST. PART 111. 953 that under these conditions equal quantities of sugar were fermented in equal times. If no change had taken place in the fermentative power of the yeast during the experiment, this result would negative the enzyme theory.I t is, however, quite possible that the fermenta- tive power of the yeast has changed in the course of the experiments, and for the following reasons. It is shown in Table 4 that fermentation is closely connected with yeast growth, and if yeast growth has taken place, the fermentative power of yeast as a whole has probably changed. Now, in two of A. J. Brown’s experiments (Zoc. cit., 377), in which a large excess of yeast was employed, and no numerical increase took place, the weight of the yeast had appreciably increased during the ferment a t ion. Moreover, J. O’Sullivan (J. Fed. Inst. B~ewing, 1899, 5, 101) showed that whilst the invertive function of living yeast could be and was usually exercised without yeast growth taking place, this was not the case with the fermentative function.Other evidence in- dicating the intimate connection between yeast growth and fermenta- tion is to be found in the experiments described above (statements 4 and 5) and in the stimulating effect of nutriment in increasing the rapidity of fermentation of a non-multiplying yeast (J. O’Sullivan, J. SOC. Chem. Ind., 1898, 17, 559). Even supposing that, by using a large excess of yeast, i t mere possible to obtain fermentation, without any apparent increase either in the weight of the yeast or in the number of yeast cells, yet it would be quite possible for yeast growth to take place a t the expense of the decomposition products of dead cells which are always present, decom- posed yeast being an excellent yeast food, If yeast growth has taken place, there will probably be some change in the fermentative power OF the yeast as a whole. The experiments of Dumas and Brown do not then disprove the enzyme theory. There is thus no proof that the fermentation of sugar by yeast is not caused by an enzyme, and whilst the converse has not yet been definitely proved, the evidence at present available points in this direction. The enzyme (if existent) is exceedingly un- stable; i t diminishes in amount, even in living yeast cells which have remained quiescent for a short time,* but when required by growing yeast i t is abundantly secreted. This view derives some support from the fact that the change in the appearance of the yeast cells when sown in a fermentable soIution is similar to that which takes place in the columnar cells in the germinating barley embryo when secreting diastase. * Buchner and Rapp (Bey., 1897, 30, 2668) state that it can only be prepared from fresh yeast.

ISSN:0368-1645    

DOI:10.1039/CT9017900943

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

954 NAYLOR AND DYER: OROXYLIN. By WILLIAM ARTHUR HARRISON NAYLOR and CHARLES STANLEY DYER. THE bark of Oroxyluin indicunz mas examined by Naylor and Chaplin in 1890 (Year Book of Pl~ccrnzc~cy), and among the substances then separated was a yellow, crystalline compound, to which they gave, provisionally, the name of oroxylin. Its conduct towards certain reagents was noted, and particularly its behaviour with sodium and potassium hydroxides, which resulted in the production of an intense red colour, quickly passing into a dark green. For the opportunity to study more intimately this interesting con- stituent, we are indebted to Mr. David Hooper., of Calcutta, who kindly collected and shipped to one of us a considerable quantity of the bnrk. Isolation of Oroxylin. The bark, reduced to No.20 powder, was exhausted with 90 per cent. alcohol by percolation, the percolate concentrated by distilling off most of the spirit, and the resulting liquid poured into eight times its volume of water, when the oroxylin was precipitated together with wax, fat, and resinous substances. The bulky precipitate was collected, washed with water, and dried in a water-oven. When quite dry, it was treated with chloroform until most of the wax, fat, and resinous substance had been withdrawn. It was then exhausted with ether, the ethereal liquid distilled, and the residue washed with light petrol- eum to remove the last traces of fat. This purified residue was dis- solved in alcohol, in which it readily dissolved. The solution, after filtration, was diluted with hot water until a faint cloudiness appeared, and set aside to crystallise.It crystal- lises in sharply defined, golden-yellow needles about 1/6 inch in length, is readily soluble in alcohol or hot glacial acetic acid, less so in ether, sparingly so in chloroform, and practically insoluble in water. Oroxylin begins to melt at 225O. When burnt with cupric oxide in a current of oxygen, the following numbers were obtained : The yield of pure oroxylin is about 2 parts per 1000. C19H1400 (1). (2). (3) Werner. requires C . , . .. , , , , 67-42 67.43 67.49 67.45 per cent. H ...... 4.51 4.6 4.38 4.14 ,) For the purpose of comparison, we give the percentage numbers obtained by Werner (Pharm. Journ., 1898, [iv], 7, 390)) and it will be noted that ours are in close agreement with his.From these figures,NAYLOR AND DYER : OROXYLIN. 955 and others to be presently mentioned, me believe the formula for oroxylin to be CI,Hl,O,. AS oroxylin rapidly reduces silver compounds, the formation of a definite silver salt was not possible. The addition of lead acetate dissolved in weak alcohol to an alcoholic solution of oroxylin gives a light red, bulky precipitate of indefinite composition. Devivntives of Oroxglin. Friacetyloroxylin, C,,H, O,H,O,),.-In our first attempt to acetylate oroxylin we acted on it direct with acetyl chloride, but the method proved unsatisfactory, the product being resinous and the yield of crystallisable substance disproportionately small. Eventually, the acetic anhydride and dry sodium acetate were adopted.The action which in the early stages took place rapidly, on the application of the heat of a water-bath, mas complete in half an hour. To isolate the derivative, the mixture, after the addition of a little ether, was poured into water. The ether was blown off, when the in- soluble product gradually solidified. It was collected, washed with water, then cautiously with ether which removed resinous matter, and finally was crgstallised from alcohol. This colourless product con- sisted of minute, white, acicular crystals melting a t 150-152' with partial decomposition into oroxylin. When hydrolysed by warming for half an hour with slightly diluted sulphuric or hydrochloric acid and then pouring the liquid into water the regenerated oroxylin is precipitated, and may be collected, mashed with water, dried at 110", and weighed.In this manner, the following results were obtained froin the acetyl derivative by hydrolysis : (i) 0.2'79 gave 0.205 oroxylin, equivalent to 73.47 per cent. On cooling, the whole solidified, forming a crystalliiie mass. (ii) 0.302 ), 0.220 ,, ?, 72.84 y , (iii) 0.430 ,, 0.314 ,, 7, 73.02 ,, Cl,Hl,0,(C2H,0)3 contains oroxylin = 72*S4 per cent. Dibrornovoxglin, C,,H,,O,Br,.-One gram of oroxylin was dissolved by heating with 20 C.C. of glacial acetic acid, and to the solution was added 1 C.C. of bromine. The mixture was allowed to evaporate on a water-bath until i t commenced to crystallise, when it was set aside and the mother liquor poured off from the crystalline magma. The product, after three recrystallisations from acetic acid, was obtained in pale yellow needles which began to melt at 1'73' and dissolved readily in alcohol or ether.0.308 gave 0.233 AgBr. Br =32*19. 0.428 ,) 0.320 AgBr. Er = 31.81. C,9H,20,Br, requires Br = 32.23 per cent.056 NAYLOR AND DYER: OROXYLIN. Deconaposition Products. Oroxylin was boiled for half an hour with a 50 per cent. solution of caustic potash, When cold, it was diluted with water, neutralised with hydrochloric acid, and agitated with ether. The ethereal lager yielded a small quantity of a neutral substance, which, after puri- fication, answered the test for phloroglucinol with pinewood and hydrochloric acid. The neutralised liquid was then acidified and again shaken with ether, The ethereal layer left, after evaporation, a much coloured residue.The crude product was extracted with light petroleum, which by slow evaporation gave a crop of fine, colourless needles having an aromatic odour. This crystalline sub- stance sublimed unchanged, melting a t 1209 An aqueous solutioa, when neutralised by caustic soda, gave a reddish-brown colour with neutral ferric chloride. Its melting point, solubilities, and behaviour towards reagents afford conclusive evidence that it is benzoic acid. A second quantity of oroxylin was similarly treated with a 20 per cent. solution of caustic potash with a similar result, except that in addition to benzoic acid a small quantity of phthalic acid was detected. A third quantity was digested for half an hour with fused potash maintained a t a temperature of about 180'.Again the chief pro- duct proved to be benzoic acid. When oroxylin was allowed to stand in a 5 per cent. solution of potassium hydroxide at the ordinary temperature, a considerable liberation of benzaldehyde occurred. Potassium permanganate is instantly decolorised by oroxylin, phthalic acid being one of the products of the reaction, as recognised through the fluorescence resulting from the interaction with resorcinol. The following negative results indicate the absence of a methoxyl or ketonic group in oroxylin, and also prove that it is not a weak acid. 1. The application of Zeisel's method for the estimation of meth- oxyl gave negative results, 2. When treated with a mixture in suitable proportions of pot- assium iodide and iodate, there was not the faintest liberation of iodine. 3. Several attempts were made to induce oroxylin to interact with phenylhydrazine, but without success, neither phenylhydrazine in the. presence of acetic acid, nor its hydrochloride, with or without acid, sufficed to convert it into a hydrazone. Summarising the results at present obtained, it appears that oroxylin forms a dibromo-derivative, that i t contains an easily de- tached benzene nucleus, that three hydroxyl groups are present, and that its composition may be represented by the formula C,,H,,O,.

ISSN:0368-1645    

DOI:10.1039/CT9017900954

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

OPTICALLY ACTIVE DIMETHOXYSUCCINIC ACID. 957 CII.-Optically Active Dirrzethoxysucciizic Acid and its De yivatives. By THOMAS PURDIE, F.R.S., and JAMES C. IRVINE, B.Sc. PREVIOUS papers on the use of silver oxide and alkyl iodide in alkyl- ating the esters of hydroxy-acids have shown that optically active mono- and di-alkyloxysuccinic and alkyloxypropionic acids can be readily obtained from active malic, tartaric, and lactic acids by this method. The alkyloxysuccinic acids mentioned are substances of considerable interest from a stereochemical point of view. Their close relationship to the common hydroxy-acids, which have formed the subject of so much research in this particular field, imparts of itself a special interest to them. Their etheric character protects them from the disturbing effects which the hydroxyl group is known to exercise on optical activity, and unlike most of the acyl derivatives of the hydroxy- acids, they can be examined as free acids or salts i n solution without risk of decomposition. They are endowed with much higher optical activity than the parent acids, and are therefore well adapted for the investigation of problems relating to this property.We have already described various representatives of this class of optically active compounds, but i t is evident that if general conclusions are to be reached on the points raised by their study, more extensive series of them must be examined. The present paper deals with dimethoxysuccinic acid, its methyl, ethyl, and prop91 esters, and some of its metallic salts.Jfetlql d-l)inLetl~o~~succiIaate. The observed rotation of the methyl tartrate used in the prepara. tion of this compound was + 2.82' in the superfused state ( I 3 1, t = 20'), the corresponding value recorded by A. Pictet being 2.84O. On adding the silver oxide (3 mols.) to the solution of the tartrate (1 mol.) in methyl iodide ( 6 mols.), a vigorous action ensued, which had to be moderated by cooling. After heating the mixture for some time on a water-bath, filtering, and distilling off the ether which was used in washing the silver iodide, a liquid was obtained which boiled nearly constantly at 132' under 12 mm. pressure and gave a distillate which crystallised quickly in radiating prisms. The substance, after being recrystallised from ether, melted a t 51°, and gave on analysis : I.C=46*70; H=7.12. 11. C = 4 6 * 5 5 ; H=6*98. C,H,,O, requires C = 46.60 ; H = 6.80 per cent,958 PURDIE AND IRVINE OPTICALLY ACTIVE The compound is readily soluble in water without undergoing per- ceptible hydrolysis, also in alcohol, benzene, or chloroform, and may be conveniently crystallised from carbon disulphide or ether. Unlike methyl tartrate, it cannot be kept superfused, and the rotation of the pure liquid had therefore to be taken at 60'. The result was a= + 93.48', I = 1.001, d 60°/4'= 1.1317, hence [U]T= + S2.52'. I n preparing ethyl diethoxysuccinate from ethyl tartrate (Zoc. cit.), the crude product contains a considerable quantity of a less active compound, which is removed with some difficulty. The reaction between methyl tartrate and methyl iodide, on the other hand, gives an almost quantitative yield of dimetboxysuccinate ; from 45 grams tartrate we obtained 46 grams of the recrystallised substance.The fact that three different preparations showed practically the same specific rotation, namely, + 104*66', 104*47O, and 104.60' in at 10 per cent. benzene solution at 20°, indicates that racemisation does not occur in the course of the chemical action, and this was further con- firmed by finding that fractional cry stallisation produced no appreciable change of activity. Ethyl d-Dimethoxysuccinate. I n preparing the alky loxypropionic esters containing two different alkyl groups (Trans., 1899, 75, 486), it was found that the hydroxyl of the ethereal lactates can be alkylated with silver oxide and alkyl iodide without any interchange with the carboxylic alkyl group occurring. We find that tartaric esters behave similarly, ethyl dimethoxysuccinate being produced by the action of methyl iodide and silver oxide on ethyl tartrate.The ethyl tartrate used in our preparations gave a= + 94110 (I= 1, t=20°), Pictet's value being 9.24'. The proportion of materials and the method of procedure were the same as described above ; the reaction here was apparently less vigorous, and a perceptible quantity of water was produced. From 41 grams of ethyl tartrate we obtained 45.5 grams of a thick, yellowish oil, which boiled at a cearly constant temperature, and gave the rotation a2O0== 95*96O (Z= 1). The methods used in the case of the methyl ester, for assuring ourselves t h a t the action was com- plete, not being available, the product was subjected to further treat- ment with silver oxide and methyl iodide.h second treatment with a third of the quantities of the reagents originally used raised the rotation to 98.66'; after a third similar treatment, the rotation found was 98-47', and after another distillation (b. p. 155' under 25 mm. pressure) 98.61'. The substance was accordingly regarded as pure. Analysis gave : C = 51.33 ; H = 7.82. C,,H,,O, requires C = 5P28 ; H= 7.69 per cent.DIMETHOXYSUCCINIC ACID AND ITS DERIVATIVES. 059 The compound was further identified by analysis of the dried barium salt obtained from it by hydrolysis wibh barium hydroxide, which gave Ba = 43.91, the calculated number for barium dimethoxy- succinate being 43.77, and by the fact that the acid prepared from this barium salt possessed the same activity as that prepared from methyl tartrate in the reaction already described.The ester did not solidify, and was much less soluble in water than the methyl homologue. Specific rotations taken in a 1 dcm. tube gave : d lOo/4'= 1,1055, [ a ] T = + 90*70°. CZ 15°/40=1*1020, [ a ] r = 90.26. d 20°/4'=1.0961, [.IF.= 8 9 - 9 6 . d 60°/40= 1.0556, [ a]F7 = 85.39 . Propyl d- Dinaeth oxgsuccinnte, We are indebted to Mr. E. J. Balfour, who is preparing some of the higher dialkyloxysuccinic esters, for the following data concerning this compound : +90*12O, Z = 1 , d 20°/40=1*0612, [u]$" = +84*92O. u t i O O - - + 82*98O, Z=1, d 60"/4'= 1,0237, [.I:"= + 81.06".d-Dimethoxysuccinic Acid. This acid was prepared from the methyl ester by hydrolysing it with a 10 per cent. aqueous solution of potassium hydroxide, acidifying, and extracting with ether, and also from the methyl and the ethyl esters by hydrolgsing with barium hydroxide and decomposing the crystallised hydrated barium salt with the calculated quantity of sulphuric acid. The latter is the preferable method, as ether does not extract the acid easily from an aqueous solution. The compound is readily soluble in water, alcohol, or acetone, much less so in ether, and is scarcely dissolved by benzene or carbon disulphide. It crystallises from water in small prisms and from acetone in largeplates. Crystals obtained from an aqueous solution, after drying in a vacuum, melted a t 151°, but not very sharply, owing perhaps to slight decomposition.Analysis of the acid, dried a t loo', gave C = 40.26 ; H = 5.77. C,H,,O, requires C = 40.45 ; H = 5.62 per cent. Observations on the rotatory power of the acid in solution are recorded below. The diacyl- and dialkgl-succinic acids in general yield anhydrides readily, and the dialkyloxysuccinic acids might be expected to behave similarly. Our attempts, however, to prepare dimethoxysuccinic960 PURDIE AND IRVINE : OPTICALLY ACTIVE anhydride were not successful. When the dry acid was treated with boiling acetyl chloride, and the excess of the reagent then evaporated, the residual liquid deposited well formed cubes, which melted a t a much lower temperature than the acid, namely, at about 77", and the substance still retained the low melting point after recrystallisation from chloro- form.On recrystallising, however, from boiling ether, needles were obtained which had approximately the same melting point as the acid. The melting point rose in a similar manner on heating the substance at loo", and on letting it stand for some days at the ordinary tem- perature in a vacuum. The low melting point might perhaps be due simply to solvent adhering to the acid, and the subsequent rise to its removal, but the observations suggest the possibility of isomeric change, and we intend to examine the reaction with larger quantities of material. An attempt to convert the acid into anhydride by dis- tilling in a vacuum resulted in complete decomposition.d- Dimethoxysuccinamide. When a concentrated solution of the methyl ester in methyl alcohol was saturated with ammonia, this compound was deposited slowly in the form of a mass of felted needles. After being dried at loo", it was analysed with the following results : I. C = 40.86 ; H = 7-22, 11. C = 40.84 ; H = 7.10 ; N = 16.09. C6H,,0,N, requires C = 40.91 ; H = 6.82 ; N = 15.91 per cent. The substance is insoluble in the ordinary organic solvents, and very sparingly soluble in cold water, but more soluble in boiling water, from which i t crystallises unchanged. As the following observations of its optical activity had consequently to be made on very dilute aqueous solutions, the results are only approximate. c = 0.72, I = 2, a2O0= + 1*36", hence [a]T= + 94.44".The amide was prepared*with the object of obtaining the imide from it by the action of heat, as an examination of this sub- stance, it was thought, would throw some light on the influence of ring formation on optical activity. The amide did not suffer any loss of weight when heated to 160" in an air-bath, but when heated strongly in a test-tube it fused and volatilised with a considerable evolution of ammonia and some charring. By distill- ation in a vacuum on a graphite bath, the substance entirely sublimed without fusion or charring in beautiful needles an inch long, which resembled the original substance in respect of insolubility and difficult fusibility, but showed a considerably higher specific rotation, namely, + 105.9'. A combustion giving -C = 40.80, H = 7-18 per cent.proved,DIMETHOXYSUCCINIC ACID AND ITS DERIVATIVES. 961 however, that the substance was unaltered amide, the high rotation being due probably to the presence of a small quantity of some more active product. Metallic d-Diinethoxysuccinates. The diammonium and ammonium hydrogen salts both crystallise readily, the former in needles, the latter in prisms. The dipotassium salt is very soluble, and was not obtained in definite crystals; the hydrogen potassium salt crystallises in radiating needles. The silver salt is very soluble in water and decomposes when its solution is evaporated, The magnesium salt on evaporating its solution leaves a gum, which solidifies to a glass. The following salts, whose rota- tory powers were observed, were analysed ; the numbers given are the percentages of metal in the dehydrated salt.Disodium Salt.-Feathery aggregates very : oluble in water. Found Na = 20.80 ; calculated 20.72 per cent. Sodium Hgdrgen Salt.-Minute prisms, less soluble than the normal salt, anhydrous at 100". Found, N a = 11.36 ; calculated, 11.50 per cent. Barium Salt.-Well developed, short prisms containing 5 mols. of water of crystallisation; sparingly soluble in water. Loss of water at, 168" ; H,O = 22.27 ; 5H,O requires 22-31. Found, Ba = 43*65,43*72 ; calculated, 43.84 per cent. One hundred C.C. of a n aqueous solution saturated at 20" contained 1.38 grams of anhydrous salt. Calcium SaZt.-Piisms, fairly soluble, containing 2 mols. of water of crystallisation, which are given off entirely only at about 160'.Loss of water; H,O=14*62, 14.22; 2H,O requires 14.28. Found, Ca = 18.55, 18.47 ; calculated, 18.52 per cent. Zinc XaZt.-Aggregates of prisms, containing 2 mols. of water of crystallisation, which are lost a t 160". Loss of water; H,O= 12.88; 2H,O requires 12-98. Found, Zn = 26.71, 27.03 ; calculated, 27.09. A solution saturated at 20" contains about 4.4 per cent. of anhydrous salt . The rotations of the acid and its metallic salts in solution are tabu- lated below. The observations were taken at 20" in a 2 dcm. tube, One or more solutions of each substance were prepared, and the others of different concentration were procured from these by dilution ; in the case of the acid and the sodium hydrogen salt, the quantities used were weighed, and the solutions made up to known volumes at 20°, but i n the case of the other salts, as they could not be dehydrated without a risk of impairing the activity, the concentrations were ascertained by weighing the dry residues left on evaporating known volumes, and controlling the result by estimat.ing the metal by in- cineration.The acid and salts were in general examined in solutions of nearly equivalent strength ; the approximate concentrations with962 PURDIE AND IRVJKE : OPTICALLY ACTIVE respect to anhydrous substance, in terms of a normal solution, are given in the column headed N. Rotatoi*y powers of solutions of d-dimethoxysuccinic acid and its salts. Substance. Acid.. .................... ) ) ....................... , , ....................... ,) ......................,, ....................... ,, ....................... 7 , ....................... Sodium hydrogen salt Disodium salt ........ Barium salt ........... Calcium salt ............ $ 9 3 , 3 , ? ¶ $ 9 7 9 Zinc salt ................. 9 , 9 9 9 9 Discussion of Results. C. 8.9091 3.5595 1.7797 17.5839 8'9104 4'4570 1 -781 2 10.0116 5.0078 2.0000 10 *1755 5.0830 2.0370 1.3775 10.6535 5-3160 2.1350 4-3690 2'1845 1 -0923 0.5461 + 89-29" 91.30 95.80 72.28 74 *74 75.39 76.63 57-03 57'31 58-50 52.68 53-02 54-00 27'22 43.83 46'37 - 5.95 +6'18 17-39 36.62 42-38 + 158'9'' 162.5 170.5 128.7 133.0 134.2 136.4 114'1 114'6 117'0 117.0 117.7 119'9 85'2 91'5 94.7 100.2 - 14.4 + 14'9 42 00 88'4 Ethereal Dirnethoxysuccinates. The ethereal tartrates, like the malates and lactates, exhibit a re- markable rise of optical activity when their alcoholic hydroxyl is slkylated.It seems probable that the alkylation with silver oxide and alkyl iodide is effected by simple substitution, possibly through the formation of an intermediate unstable silver derivative, and it is therefore very unlikely that any inversion of configuration occurs, such as Walden encountered in the interconversion of malic and chloro- succinic acids. As, however, in the opinion of its discoverer (Ber., 1899, 32, 1864), the change of configuration in this case occurs during the hydrolysis of the halogen-succinic acid by silver oxide, and as this re- agent was also used in our method of alkylation, we thought i t well to assure ourselves that no inversion bad taken place, by reconverting the dialkyloxysuccinic acid into tartaric acid.It will be seen in the succeeding paper that by the action of liydriodic acid on dimethoxy- succinic acid &-tartaric acid is produced. The ethereal tartrates and dialkyloxysuccinstes. of similar sign of rotation possess therefore a similar configuration, and the effect of alkylating the tartrates is to largely increase the dextro-rotation, This effect differs in a markedDIMETHOXYSUCCINIC ACID AND ITS DERIVATIVES. 963 degree from that produced by the introduction of acyl groups into the tartrates, which either alters the rotation in the positive sense com- paratively slightly, or more frequently produces an effect in the opposite direction, It is now generally recognised that the influence of substitution on the optical activity of a compound depends more on the chemical nature of the introduced group than on its mass, and that radicles of a like kind cause changes of rotation which are similar with respect to direction, and similar also, in a general sense, quantitatively. This point has been brought forward prominently in recent communications to this Journal by Frankland and his pupils (Trans., 1900, 77, 1108; 1901,79, 511), and by Guye (Trans., 1901, 79, 475).The following data selected chiefly from Frankland's paper (Zoc. cit.), to which we add our own observations on mono- and di-alkyloxysuccinates, will suffice to show the relative effects of the introduction of alkyl and acyl groups into ethyl tartrate and malate. To facilitate the comparison of the two series of compounds, we have halved the molecular rotations of the tartrate derivatives, and have regarded the malic compounds as derived from d-malic acid, the stereo-chemical analogue of d-tartaric acid.~~ ~ ~~ Malic derivatives. Ethyl monoethoxysuccin ate * ......................... Ethyl monome t hoxysuccin ate * ......................... Ethyl bromoacety lmalate.. Ethyl acetylmalate t ........ Ethyl malate t .............. Ethyl benzoylmalate.. ..... Ethyl p-toluylmalate ...... 17" 18 20 , 9 7 9 21 20 - t 121-0" 102.2 69 '9 52.4 20'2 11.4 0.68 Tartaric derivatives. Ethyl diethoxysuccinate : Ethyl dimethoxysuccinatc Ethyl diphenacetyltar- trate.. ....................... Ethyl dimonochloroacetyl~ tartrate ..................... Ethyl diacetyltartrate ......Ethyl tartrate ................ Ethyl dibenzoyltartrate ... Ethyl di-p- toluyl tartra te.. - to. + 122'1" 105.3 39'6 12.8 4.95 7 '93 - 123.6 - 242.2 * Trans., 1895, 67, 979. i- Zeit. physilld. Chena., 1895, 16, 495. $ Trans., 1899, 75, 159. rotation given is probably about 2" too low. A later preparation of this compound shows that the It will be seen that, with respect to their influence on the rotation of both malate and tartrate, the alkyl radicles stand a t the positive, the aromatic acyl groups a t the negative, end of the scale, whilst the fatty acyl groups, including phenacetyl, hold an intermediate position. The effects of the substitution of the hydroxylic hydrogen of the ethereal lactates by alkyl radicles (Trans., 1899, 75, 487), and by benzoyl and acetyl radicles (Proc., 1895, 11: 54), show a similar relation.964 PURDIE AND IRVINE : OPTICALLY ACTIVE Considering the members of the tartaric series as derived from the corresponding rualic compounds by the introduction of OR into the group CH,*CO,Et, it might be supposed that this substitution, occurring not in immediate proximity to the asymmetric carbon atom, would possibly not affect the rotation greatly.The supposition proves, in fact, to be correct with respect to the introduction of the alkyloxy- radicle into the monoalkyloxysuccinate, the dialkyloxysuccinates having, as will be seen, approximately the same rotation as the monoalkyloxysuccinates. The introduction of hydroxyl, on the other hand, into ethyl malate, or of an acyloxy-group into the corresponding acylmalate, produces a marked effect, which shows itself in the rota- tions of the tartrate and its derivatives by a gener.al shifting of the values in the laevo-direction.That is to say, the rotation of the mono- alkyloxysuccinate is scarcely affected by the introduction of a second alkyloxy-group ; the dextro-rotation of the malate is considerably reduced by the introduction of another hydroxyl group, whilst with the acylmalates the effect of the substitution is still greater in the same direction, the slight dextro-rotation, for instance, of the p-toluyl- malate becoming a powerful laevo-rotation in the di-p-toluyltartrate. It is impossible a t present to offer any explanation of this difference in the behaviour of the monoalkyloxysuccinates and acylmalates with respect t o the effect of further substitution ; it may be due either to the difference in the nature of the introduced groups or to the different states of dissymmetry of the parent monosubstituted compounds, or to both causes combined.I n view of recent researches, and more particularly of Frankland’s exhaustive survey of the known homologous series of optically active compounds, which exhibit a maximum rotation (Trans., 1899,75,347), it must be admitted that the attempt to find a relation between Guye’s product of asymmetry and the rotatory powers of compounds has not met with success, and will probably have to be abandoned. Although failure has attended this attempt, the more general form of the original conception put forward by Guye and Crum Brown still survives, and may serve as a guide in research.According to this conception, the measure of rotatory power may still be represented as the product of the differences of each pair of four coefficients, the values of which, however, are conditioned by other factors besides mass, and a pro- gressive variation in the value of one of these may result in the occur- rence of maxima of rotation. Homologous series, therefore, in which the phenomenon of a maximum rotation is found, still deserve particular attention. It will be seen, from our abservations tabulated below, that the specific rotations of the three dimethoxysuccinic esters at 60° show a diatinct maximum at the ethyl term.DIMETHOXYSUCCINIC ACID AND ITS DERIVATIVES. 965 [a]?. [1f]r.[a]:'*- Methyl.. ............ - - 82'5 Ethyl ............... 90.0 210% 85.4 Propyl ............. 84.9 222'4 81.1 hfol. vol. Mol. vol. [MI:'. calculated experi- for 15". mental. 170.0 151'5" 182.0 (60") 199.8 213.7 212.3 (15") 212.5 245.9 2 4 6 9 (20") It mas impossible to take observations on the methyl ester at lower temperatures, but even if the rise of rotation attending the fall of temperature from 60° to 20° were greater for this compound than for the other two, which might be the case, the maximum rotation exhibited by the ethyl term would probably still persist a t 20°, Frankland (Zoc. cit.) concludes, from certain considerations, alluded to below, that the maxima of specific rotation exhibited by the ethereal malates and lactates are probably attributable t o the depression of the rotations of the lower members of the series by molecular association.The maximum exhibited by the dimethoxysuccinates cannot, however, be accounted for in this way. The methyl ester, it is true, according t o Traube's method of caiculating association factors, should be con- siderably associated a t ZOO, as its experimental molecular volume, even at 60' (see the Table), is only just in excess of the value calculated from his constants, which refer to 15', and the ethyl term is little, if a t all, associated a t the lower temperature. It is shown, however, in the succeeding paper (p. 973), that the specific rotation of the methyl ester at 20' in water is 7S.5', and that the substance under these con- ditions has a normal molecular weight ; that is to say, the dissociating solvent, water, lowers the rotation to a value even below that of the pure liquid a t 60°, whilst the rotation of the ethyl compound, i t was found, is little affected by water.Assuming, then, in accordance with prevalent ideas, t h a t associated molecules are present in the pure liquid methyl ester, and that they influence the rotation, their effect would be to raise it, and, consequently, were the methyl compound in the unimolecular condition, the maximum exhibited by the ethyl term would be still more pronounced. The molecular rotations, it will be seen, increase from the methyl term upwards but tend towards a maximum. The completed series would probably present the same phenomena as others in which a maximum occurs, of which Guye and Chavanne's amyl esters of the fatty acids (Bull.Xoc. China., [iii], 1896, 15, 183, 275), Reitter's ethyl acetylmalates (Zeit. phpsikal. Chew., 1901, 36, 164), and Frankland's VOL. LXXIX. 3 u966 PURDIE AND IRVINE : OPTICALLY ACTIVE glycerates and diacetylglycerates (Trans., 1894, 65, 755) are typical, namely, a rise of molecular association to a maximum, which either remains nearly constant or is followed by a more gradual fall. Frankland, in the paper already quoted, suggests that the phenomenon of maximum specific rotation exhibited by certain homologous series is probably attributable to two distinct causes; in the case of the ethereal malates and lactates, the maximum is only apparent, being reasonably explicable as due to the association of the initial terms; in that of the tartrates, glycerates and diacetylglycerates, the maximum cannot be thus accounted for, and is due to some other cause.He is led to this conclusion by the observation that, whilst ethyl malate has a higher specific rotation than methyl malate, the order of the values for the corresponding benzoyl- and toluyl-malates is reversed, this phenomenon being coincident with the fact that the malates, on the evidence of Traube’s method, are associated (the methyl term, however, much more so than the ethyl term) and the acylmalates, referred to, un- associated. He finds similar relations on comparing the malates with Walden’s fatty acylmalates and chlorosuccinates, and concludes that it is not improbable that the real values of [aID for the unimolecular malates diminish in passing up the series from the methyl term.A similar argument and conclusion apply to the lactates. On the other hand, the maximum rotation observable in the tartrates, glycerates, and diacetylglycerates cannot, he thinks, be thus explained, because it is so very pronounced, and because in their substitution compounds, which show little or no evidence of association, the relationship between the rotations of the methyl and ethyl esters is retained. We doubt if the facts really warrant this explanation of the maxima of rotation presented by the malates and lactates. First, with respect to the reversed order of the specific rotations of the initial terms of the series of substituted malates, the reversal in question is not quite general.The decrease of values on ascending the series of fatty acylmalates is so slight and irregular as to be within the limit of experimental error, and the case of the chlorosuc- cinates cannot be cited in support of the hypothesis, if Walden’s views, (Ber., 1899, 32, 1864) published since Frankland’s paper, are correct. In Walden’s opinion, the dextrorota tory chlorosuccinates correspond in configuration to theZ-malates, and ought, therefore, according to the hypo- thesis, to show an increase of rotation with ascent of the series instead of a pronounced decrease which they actually exhibit. Further, we doubt if the assumption on which the hypothesis is based is warranted. It is assumed, namely, that when a series of esters is transformed by sub- stitution into a new aeries, if the supposed disturbing influence of association is absent, the members of the substituted series will present the same order of rotation values as the parent series, each rotationDIMETHOXYSUCCINIC ACID AND ITS DERIVATIVES.967 being simply shifted by a certain amount in the positive or negative direction, as the case may be. This may not, however, hold true, for independently of any effect due to changed degree of association, the substitution may influence the state of dissymmetry of successive members of the series in different degrees and so produce a considerable change in the relation of their rotation values, or even reverse their order from the first term onwards. The dimethoxysuccinates present a case in point. By methylating the tartrates, the maximum specific rotation of the series is displaced from the propyl to the ethyl term, with the result that, although none of the compounds concerned are, according to Traube’s method, affected by association, ethyl dimethoxy- succinate has nevertheless a higher specific rotation than the propyl compound, whilst, of the corresponding tartrates, the prop91 compound has the higher rotation.I n default of more conclusive evidence, we incline t o the view that, although the rotations of the initial terms of the series of malates and lactates may probably be lowered to some extent by molecular associa- tion, the maxima of rotation exhibited by them is attributable to the same causes as those of the tartrates and other series, The discussion of this subject raises the fundamental questions of the influence of molecular association on rotation and of the trust- worthiness of Traube’s method of determining the association factor.In the succeeding paper, it is shown that solvents may’produce marked changes of rotation without any change of association, and that association may be similarly produced without change of rotation ; association evidently does not play a predominant part in the changes of rotation due to solvents, and it is extremelydoubtful if it has much influence in the case of pure liquids. Traube’s method of determining the association factor has not met with general acceptance, and it is doubtful how far its results may be relied on. The association factors of the lower members of a homologous series of esters deter- mined i n this manner are frequently greater than unity, and diminish gradually, on ascending the series, to the latter value; this is inter- preted in discussions on optical activity as indicating gradually decreasing molecular association, but it is commonly ignored that on ascending further i n the series the value of the factor does not remain constant, but continues to decrease steadily, and yet the latter phenomenon is surely equally significant with the former.This decrease can scarcely be held to indicate dissociation, and the more obvious conclusion seems to be that on ascending the series there is a gradual increase of molecular volume in excess of that due to the in- crease of mass, caused, it may be supposed, by a lessening of the internal forces of the liquid.The molecular expansion which accompanies the passage upwards through the lower members of a 3 u 2968 PURDIE AND IRVINE : OPTICALLY ACTIVE series, such as the esters of the hydroxy-acids, is due, no doubt, partly to disgregation of associated molecules, but the expansion evidently does not cease at the term where association is supposed to disappear, but extends indefinitely through the series. This suggests a doubt whether in such series Traube's method can be relied on for ascertain- ing even roughly the degree of association or the point in the series where association ends. T. 8. Patterson's views on the cause of the changes of rotation produced by solution (Trans,, 1901, 79, 167, 477) suggest the ides that the changes of rotation attending the ascent of a homologous series of homogeneous liquids may also be due largely to the lessening of the internal forces, manifested in the abnormal increase of mole- cular volume above referred to.Xolutions of Dimethoxysuccinic Acid and its Xults. The rotation of dimethoxysuccinic acid in aqueous solution is more constant, as was to be expected, than that of tartaric acid; it in- creases with dilution, like ihat of the hydroxy-acid, but the relative increase is much less. Dimethoxysuccinic acid, however, does not exhibit quite such a constant rotation as the monomethoxy-acid (Trans., 1895, 67, 949), and the two acids do not show the quan- titative relation presented by their ethyl esters (p. 969), half the molecular rotation of the former (68.2') being much in excess of that of the latter acid (48.9O).The ion of the former acid, as pointed out below, is also more active than that of the latter. It is worthy of notice that in acetone solutions, on the other hand, in which the rotations of both acids are much raised, the relation in question holds good, the mole- cular rotation of the monomethoxy-acid ( 8 8 9 , Zoc. cit.) approximating to half that of the dimethoxy-acid (85.2'). With respect to the salts, in dilute solution they are dextrorotatory like the acid and its esters, and their rotations increase with dilution. The calcium salt shows a much greater rise with dilution than the normal sodium salt, and the molecular rotations of both barium and calcium salts in dilute solution fall further short of the maximum mole- cular rotation of the sodium salt than the law of Oudemans and Landolt would lead us to expect.The monoalkyloxysuccinates show similar relations (Trans., 1893, 63, 239). According to van 't Hoff this behaviour of the salts of bivalent metals of polybasic acids is probably attributable to the influence of ring formation, as well as to less advanced electrolytic dissociation. This view is supported by the fact that the molecular rotations of the corresponding salts of the monobasic alkyloxypropionic acids (Trans., f899,75. 490), approximate much more closely to the maximum. On the other hand, the remark-DIMETHOXYSUCCINIC ACID AND ITS DERIVATIVES. 969 Normal alkali salt. able behaviour of zinc dimethoxysuccinnato, which even in a 4 per cent.solution is already lavorotatory, is not to be accounted for as van' t Hoff suggests, as the zinc alkyloxypropionates (Zoc. cit.) show a simi- lar abnormally rapid change of rotation with change of concentra- tion. The known low degree of electrolytic dissociation of zinc salts (Zeit. physikal. Chern., 1898, 27, 399), and hydrolytic dissociation are probably the disturbing factors hero. The rotations of aqueous solutions of the mono- and di-alkyloxy- succinic acids and their salts show some further relations which de- serve notice ; these may be seen from the following data abstracted from the present and previous papers (Trans., 1893, 63, 239 ; 1895, 67, 965 ; 1899, 75, 159). The numbers quoted are molecular rota- tions, halved in the case of the dialkyloxysuccinic compounds, and the differences given are the percentage rises of rotation between successive terms in ascending the series.Diff' Mono- and di-alhJoxysuccinnic acids. Monometboxysnccinic .. , Monoethoxysuccinic .. . , . . Monopropyloxysuccinic.. . Dimethoxysuccinic.. . . . . . . . Diethoxysuccinic . , . . , . . . . Acid. 48.9" 52 *7 63 -8 68 -2 68 -5 I- Diff. 7.8" 21.0 Hydrogen alkali salt. 43 '6" 57 .a 69'2 58'5 - - Diff. 32-6" 19-7 - I-- 21.4" 35-9 43-5 59.9 51'4 6723" 21 *2 The ethereal monoalkyloxysuccinates (Trans., 1895,6'7,979) exhibit a rise of molecular rotation in passing from the methoxy- to the corre- sponding ethoxy-compounds ; the esters of the propyloxy-acid have not yet been prepared, but it is probable that the increase will still con- tinue to this term of the series.I n agreement with the esters, the monoalkyloxy-acids, acid salts, and normal salts, as will be seen from the table, show also a rise of molecular rotation on ascending the series. The rise between the ethoxy- and propyloxy-compounds is uniform, namely, 20-21 per cent, whether acids, acid salts, or normal salts are considered, but the relations of the methoxy- to the ethoxy- compounds are quite different, the rise here being much less for the acids (7.8), much greater for the acid salts (32.6), and still greater for the normal salts (67.8). The effect of the methoxy-group, ascompared with that of the higher alkyloxy-radicles, is to raise the rotation of the slightly dissociated acid and to lower the rotation of its ion.This effect of the lowest term of this series of radicles in raising tho rota-970 OPTICALLY ACTIVE DIMETHOXYSUCCINIC ACID. tion of the acid in aqueous solution is of some interest, as it explains similar perplexing relations encountered in the alkyloxypropionates (Trans., 1899, 75, 490; 1898, 73, 874). The following diagram represents the relations of the alkyloxypropionic compounds with respect to the values of their molecular rotations, so far as they have been studied : Methoxy-ion < ethoxy-ion < propyloxy -ion Methoxy-acid > ethoxy-acid (liquid). Methoxy-esters > ethoxy-esters ( ,, ) The difference found between the rotations of the methoxy- and ethoxy-acids in the liquid state was very slight, but in general it may be said that in the case of the undissociated esters and slightly dis- sociated acids, particularly in the presence of water, the methoxyl group has a peculiar effect in raising the optical activity.With respect to the dialkyloxysuccinic compounds, the methoxy- esters are less active than the ethoxy-esters, so far as these have been examined, and it might have been expected that aqueous solutions of the two acids would show the same relation, but here again the pecu- liar effect of the methoxyl group asserts itself, with the result that the acids have nearly the same molecular rotation ; in contradistinction to what might have been expected from the relations of the monoalkyl- oxysuccinic acids, which have been indicated above, the effect of the methoxyl group in raising the rotation extends to the ion of di- methoxysuccinic acid, sodium dimethoxysuccinate having a higher molecular rot ation than the corresponding diet hox y-sal t. In conclusion, we point out a general relation which seems to hold between the hydroxy-acids and the corresponding alkyloxy-acids, which has been alluded to in previous papers (Trans., 1899, 75, 160), and finds further illustration in tartaric and dimethoxysuccinic acids. The molecular rotations of dilute aqueous solutions of the normal d-malates, d-lactates, and d-tartates are much higher in the dextro- sense than those of the corresponding free acids ; in the case of the alkylated derivatives, on the other hand, the rotations of the normal alkali salts are much lower, or, at most, only slightly higher, than those of the free acids; that is to say, the rise of rotation produced by alkyl- ntion tells much more strongly on the hydroxy-acids than on their salts. The known marked influence of hydroxyl groups on the physical properties of compounds, and the great effect of varying concentration on the rotation of aqueous solutions of the hydroxy-acids, suggests that the cause of the general relation just indicated is to be sought for in some peculiarity of the latter acids, which has the effect of lowering their optical activity. We are a t present engaged in an investigation of the higher members (aqueous solution). Methoxy-acid > ethoxya-cid < propyloxy-acid ( ,9 1INFLUENCE OF SOLVENTS ON ROTATORY POWER. 971 of the series of dial kyloxysuccinic acids and their derivatives, which we hope may throw some light on the relations of the members of the group with respect to optical activity. UNITED COLLEGE OF ST. SALVATOR AND ST. LEONARD, UNIVERSITY OF ST. ANDREWS.

ISSN:0368-1645    

DOI:10.1039/CT9017900957

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

INFLUENCE OF SOLVENTS ON ROTATORY POWER. 971 CI1I.-The In,jhence of Solvents on the Rotatory Powers o f Ethereal Dimet~~oxyszcccinates and Tai-trates. By THOMAS PURDIE, F.R.S., and WILLIAM BARBOUR, B.Sc., Berry Scholar in Science. THE observations recorded in this paper were made with the view of comparing the effect of solvents on the rotations of ethereal tartrates and their alkylated derivatives, the ethereal dimethoxysuccinates. The facts already known concerning the influence of solvents on optical activity, more particularly the extended observations of Freundler on the ethereal diacyl tartrates (Ann. Chim. PAYS., 1895, [vii], 4, 235), and the recent systematic investigation by Patterson (Trans., 1301, 79, 167, 477) of the influence of various solvents on ethyl tartrate, suffice to show that the action in question, even in the case of non- electrolytes, is very complex, and that at present no general theory on the subject can be formulated.The phenomena presented by the esters of tartaric and other hydroxy- acids are probably much complicated by the presence of the hydroxyl group, which is well known to exercise a marked influence on physical properties in general, and it appears from Freundler’s researches that, even when the hydroxyl is acylated, variations of optical activity occur under the action of solvents, for which it is difficult to discover a satis- factory explanation. Freundler, for instance, was led to conclude that the effect of benzene on the rotations of the diacyltartrates was con- nected with a peculiar form of dissociation, in which the acyl groups were split off from the compounds. It seems probable that the alkyl- ated esters of hydroxy-acids 5hould present phenomena of n less com- plex kind, and that they should be less subject, at all events, to the possible disturbing effects of molecular association than the parent esters.We purpose, therefore, investigating the action of solvents on the rotations of mono- and di-alkyloxysuccinic and alkyloxypropionic esters, and in the present preliminary paper we record observations on solutions of the three dimethoxysuccinic esters described in the pre- ceding communication, in water, methyl alcohol and benzene, We972 PURDIE AND BARBOUR: INFLUENCE OF SOLVENTS ON have also made some observations on solutions of the corresponding tartrates, but have refrained from proceeding further with these compounds, as we understand that Mr.Patterson's investigation, alluded to above, will include the whole series of tartaric esters, Conversion of d-Dirnethoxpwccinic Acid into d-Tartar ic Acid. For a comparison of the rotations of the tartaric and dialkyloxy- succinic esters, it is essential that the relationship of the two classes of compounds, with respect to configuration, should be known with certainty, As indicated in the preceding paper, i t is very improbable that in the process of alkylating the esters of optically active hydroxy- acids with alkyl iodide and silver oxide, any inversion of configuration occurs, but we thought it well, nevertheless, to set the question at rest by reconverting dimethoxysuccinic acid into tartaric acid.5 *5 grams of d-dimethoxysuccinic acid were accordingly heated with ten times the weight of fuming hjdriodic acid in a sealed tube at looo for 8 hours. The production of an oily layer, smellingof alkyliodide, indicated that the desired reaction bad occurred. The aqueous layer, after most of the hydriodic acid had been removed from it by heating in a vacuum, deposited a crystalline acid on standing in a desiccator over potash ; this, after washing with ether to remove iodine and re- crystallising from water, melted at 167'. The melting point of tartaric acid is 167-170'. A determination of the specific rotation in aqueous solution at 20° gave c=4-097, Z=2, U = +1-24', [ u ] y = +15-13', According to Landolt (Bey., 1873, 6,1075), the specific rotation of tar- taric acid under these conditions is 14-52', The sparingly soluble potassium hydrogen salt of the acid gave in aqueous solution a t 20' c=O.615, Z=4, U = + 0 * 5 6 O , [~.t]r= +22-76', the value quoted by Landolt for potassium hydrogen tartrate at the same concentration being +22-6l0. On analysis, the salt gave C = 25.66 ; H = 2.80 ; K = 20.47, 20.84.C,H,O,K requires C = 25.51 ; H = 2.66 ; K = 20.81 per cent. d-Dimethoxysuccinic acid yields d-tartaric acid by the treatment described, and as the esters in both cases are active in the same sense as their acids, it follows that ethereal dimethoxysuccinates and tar- trates of similar sign of rotation have the same configuration. I n the tables below, we give the results of our polarimetic observa- tions.The dimethoxysuccinic esters used were prepared in the same manner as the specimens described in the preceding paper, and, as will be seen from the numbers quoted, they showed practically the same specific rotations as the previous preparations. The tartrates used were obtained from Kahlbaum, and purified by fractional dis-BOTATORY POWER. 973 Water ................. tillation. I n calculating the speci6c rotation of these esters, the specific gravities quoted by Yictet mere used. The observations were taken in a 2 dcm. tube at 20'. The specific gravity of the benzene used in the solutions mas d 20°/4*=0*8785. The methyl alcohol employed was Kahlbaum's, dried by distillation from calcium oxide and from sodium; the specimen used in the observations on methyl dimethoxysuccinate had the specific gravity d 2Oo/4O = 0.1927, but that used in the other observations, having accidentally absorbed moisture, had the specific gravity 0.7946.The concentration, c (grams of substance in 100 C.C. of solution), was determined in a few instances by making up the solution of a weighed quantity of substance to a known volume, but in most cases i t was found from p (grams of substance in 100 grams of solution), and the specific gravity of the solution d 20°/40. Met ?h y 1 D inze t hoxy szc c cin CL t e. It was found impossible to take observations on the pure ester in the superfused state, but the following approximate data may be quoted, which are calculated from observations at 60' on the assump- tion that the changes with temperature are the same as in the case of the ethyl ester.19 9988 I I c. Solvent. I -___ ...............I 11.1694 Me&yl alcohol ....,.I 23'0151 ...... I 12'0806 " . * * * * I 9 ) ,, 9 3 1 6'2598 d 20"/4". - - - - - - 0.9033 0.8591 0.8276 0.8102 ~~ [a]?. + 78.71" 78q45 78'50 101-63 104'66 105.47 104 '42 78.90 76'32 81'04 - [ M ]iO". + 162.1 161-6 161 *7 209.4 215'6 217'3 215.1 162-5 157'2 166.9 Mol. sol. vol. - - - - - - 176.9 172.6 169'2 170.2974 PURDIE AND BARBOUR: INFLUENCE OF SOLVENTS ON [M1~OO- &'thy I dimethoxysuccinate. [a]:= -t89*7", [MI:= +209'9", d 20"/4"=1*0976, ill --2213*2. - d Mol. sol. vol. Solvent. I c. 1 d 20"/4". Water .................. Methyl alcohol ...... Y t ), ...... Benzene ...............) ) , .............. ,, ............... 2 ) ) ) ...... 5'3752 - P. 19.0407 0.8407 9'7365 0.8178 6.0569 0.8089 19.3137 0.9142 10.1117 0'8969 5'3130 0.8879 [a 1:. + 6.12" 6.29 6.75 + 89.1 1" 87.27 87'41 87-66 102.65 104'14 104'93 + 12%" 13'0 13.9 Benzene ............... ) ) ............... ,, ............... I 21 -0627 10.7339 5.6479 + 208 '5" 204'2 204-5 205.1 240.2 243.7 245.5 - 209.7 208.7 208-5 212% 21 2-3 213.3 Solvent. Methyl alcohol ...... Benzene ............... 2 ) )) 2 ) , , ...... ...... , , ............... ,) ............... p. 1 d 20"/4". 23.7085 12 *3697 6.6571 21'561 9 11.4730 5'6932 0,8479 0.8213 0.8086 0.9136 0.8966 0.8873 + 85-79" 84.50 84'99 99'24 101*00 101 '26 I + 224.8" 221 '4 222.7 260.0 264.6 265.3 242.3 243.1 244'0 245'1 245.7 246.3 Methyl tartrate.[a]:oo= +2'14", [M]iO"= +3*8", d 20"/4"=1-3284, '11=134-0. d Solvent. Water .................. 1 5'0231 1 1.0131 1 +20'04" I +35*7" 1 126.3 Ethyl tartrate. M d [a]?= +7%2", [MI?= +15'7", d 20"/4"=1~2059, -=170.8. Solvent. 1 p . 1 d 20"/4". I I 0.9308 0.9038 0.8913 i 1 Mol. sol. vol. 171.9 173.4 174'9ROTATORY POWER. Water .................. Benzene ............... ,, ............... ,, ............... ,, .............. 975 4.8206 1 *0071 22.2112 0'9257 11'1266 0'8993 5.4685 0.8890 5-6205 o m 8 6 Propyl tuvtrate. [a]?= + 12-31", [ M]to"= + 28'81", d 20"/4"= 1-1344, ?!= 206'3. d Solvent. Solvent. -1 p. 1 d 20°/4". Tartrate. Dimethoxysuccinate. I I Water ........................ ,, ........................... ,, ........................... Benzene ..........................Methyl alcohol ................. Methyl + 31 -9" - 17'5" Ethyl $38'2 * - 1'4 Propyl -1-33-6 slightly affected $ Ethyl -k 7.9 * - 4.8" Methyl - 19'5 j- +- 38'1 [ u1p. + 26'67' '18'31 20.34 20.78 19.62 [ M + 62.4" 42 *8 47% 48'6 45'9 Mol. sol. vol. 191.7 205'2 211'0 208*8* 212'53 * This number for molecular solution-volume is probably too low. f The specific rotation founcl by Freundler in about a 5 per cent. solution was 3- 20 -1". So far as the available data go, it may be said that, in general, the rotations of the dimethoxysuccinates are less affected by solvents than those of the corresponding tartrates, and that the action is in most cases oppositely directed. The following table in illustration of the statement shows the changes produced on the molecular rotations by the solvents mentioned at concentrations of about 5 per cent., a rise or fall of dextro-rotation being indicated by + or - respectively.I 1 * Patterson (Zoc. cit.). I- Freundler (Zoc. cit.). $ The ester is very slightly soluble in water, and the conclusion is based on an ob- servation made in aqueous methyl alcohol. Attention may be drawn to the following facts concerning the dimethoxysuccinates. Tbe three esters examined undergo a consider- able rise of rotation when dissolved in benzene, and the rotations increase with dilution, the lowest member of the series being most affected by the initial action of the solvent, and also most affected by change of concentration. The greater influence of the benzene on the fist member of the series results in the extinction of the maximum specific rotation at the ethyl term, which is shown by the pure esters,076 PURDIE AND BARBOUR: INFLUENCE OF SOLVENTS ON The effect of water and of methyl alcohol on the rotations of the three esters is, in general, in the opposite sense to that of benzene, and the first member of the series is again most affected.The rota- tion in w@ter, unlike that in benzene, is scarcely affected by ohange of concentration, at least from 20 per cent. downwards. The observa- tions on these esters in methyl alcohol present two points which are worthy of notice. First, the rotation-concentration curves of the methyl and propyl compounds exhibit a minimum, more pronounced in the curve of the former, between the concentrations of 20 and 5 per cent., a peculiar phenomenon of which Patterson (Zoc.cit.) has found striking examples in certain solutions of ethyl tartrate. The absence of a corresponding minimum in our ethyl ester is probably due to the range of concentration examined, in the case of this compound being less than in that of its two homologues. Secondly, it will be seen that whilst methyl alcohol lowers the rotations of the methyl and ethyl esters at all the concentrations examined, it slightly raises that of the propyl ester a t a concentration of 20 per cent, This peculiarity is referred to below. Finally, it may be remarked that, owing to the greater lowering effect of methyl alcohol on the first member of the series, the specific rotations of the three compounds in this solvent exhibit a more pronounced maximum at the ethyl term than those of the liquid esters.Turning to the tartrates, Freundler (Zoo. cit.) has shown that benzene in 5 per cent. solutions lowers the specific dextro-rotation of the methyl ester from + 2*14O to - 8*S0, but raises that of the propyl compound from + 12-44O to + 20*lo. H e remarks, with regard to these effects, that they are entirely irregular, It seemed to us very remarkable that the rotations of two closelyrelated members of the samehomo- IogouB series should be influenced to such a marked degree in oppo- site directions by the same solvent, and we therefore examined the effect of benzene on the intermediate ethyl ester, and also made further observations.on the prop91 ester in the game solvent. Our results with the latter compound confirm those of Freundler, and show besides that the rotation increases somewhat on dilution.We find that, with respect to the effect of benzene, the behaviour of the ethyl ester is intermediate between that of its two adjoining homologues. The specific rotation is only about 1' less than l-hat of the pure compound, and is but little affected by concentration. The effect of methyl alcohol on the dimethoxysuccinates, referred to above, gives indications of a similar reversal of the influence of the solvent on ascending a homologous series, and we are led to think that the phenomenon, to which,so far as we know, attention has not hitherto been drawn, will be found to be one of general occurrence, Freundler's data (Zoc. cit.) furnish a number of examples,ROTATORY POWER.977 of which the propyl diacetyl-, dibutyryl-, and dihexoyl-tartrates may be mentioned. Dihexoyl- Diacetpl-, Dibntyryl-, tartrate, [ €2 I”. c .I,. c U l D . Pure ester ..................... + 13.4’ + 5.2’ + 2.2’ Solution in methyl alcohol. , 12.1 9.3 5.4 ,, acetone ......... 10.4 7.2 5.3 ,j ethyl alcohol ... 9.6 6.3 3-6 Similarly, for the diacetyltattrates, alcohol and acetone lower the rotations of the ethyl and propyl and raise that of the butyl ester; also for the dipropiohyltartrates, the same solvents lower the dextro- rotatidn of the methyl ester, and raise that of the ethyl ester. Other available data indicate that, on ascending a homologous series, the effect of the solvent on the rotations tends, at least, towards a minimum, and would probably become reversed at a higher point in the series; Patterson’s observations on ethyl tartrate, and our own on the methyl and propyl esters in 5 per cent.aqueous solution at Z O O , afford an example, thus : Methyl, Ethyl, ProPYl, [ a ID’ [QID’ [ a I”. Pure ester ..................... + 2.1” 7.6” 12.3” Solution in water ............ 20*0 26.2 26.7 The cause of the phenomenon referred to is probably related to that which determines the occurrence of a maximum rotation in a homolo- gous series of liquid compounds. It might be expected that the rela- tion between the effects produced on the initial members of a series by the action of a solvent and by the addition of CH, to the active molecule of the pure liquid would be retained throughout the series, and that the effect of the solvent, like that of the addition of CK,, would therefore be reversed about the point of maximum rotation, I n the case of the tartrates, the reversal of the effect of benzene and the maximum rotation occur, as a fact, a t the same, namely, the propyl term.In general, however, the points of reversal of the influence of the solvent and of maximum rotation do not coincide. Thus, if the effect of water on the rotations of the tartrates under- goes reversal, it must be at a term higher than that of the maximum rotation; the same is possibly the case in the series of propyl diacyl- tartrates quoted above, where, as the rotations decrease from the diacetyl term upwards, i t is perhaps admissible to conceive that the point of maximum rotation lies a t or below this term. Although the facts mentioned seem to us to indicate a connection between the effect of solvents and that of the addition of mass on the rotations of the auccessive members of a homologous series, it does not follow that the978 PURDIE AND BARBOUR: INFLUENCE OF SOLVENTS ON Water .................) ) .................. ,, .................. Benzene ............... y y ............... Eth);lene dibromide. ,? ,, . ..... : ........ Y ) ,) . mechanism of the actions in altering the state of dissymmetry of the active molecules is the same, and i t is therefore not to be expected that the points of maximum rotation and reversal of the effect of the solvent should coincide. We give below the results of zt number of molecular weight deter- minations by the freezing point method in water and benzene, made with the view of discovering, if possible, a connection between the influence of the solvents on rotation and the molecular association of the dissolved active substance.S denotes the number of grams of substance in 100 grams of solvent. 3.6050 7.7713 12,7460 0'8853 24970 4.6370 0.6788 1-5300 2.3630 Solvent. 1p-l- M. Methyl dinzethoxyslcccinate, M= 206. Benzene ............ , ............ ) ) ............ ) ) ............ 1.6377 3 -4079 7'2093 7'8837 190-9 193'8 188'4 193.7 195'4 203'8 202-8 213-2 216'8 175.3 176'4 1734 Water .................. ,, .................. ), .................. 2554 296'2 34 2 *8 6'6313 5.1511 9.9887 Ethyl dimethoxysuccinate. M= 234. Benzene ...............,, ............... ,) ............... Benzene ........... ), ........... ) ) ........... 1.8194 3'8953 7'5564 3.3735 5.0373 9'0774 215.8 219-4 225'0 Propyl dimethoxyncecinate. M= 262. Benzene ............ ) ) ............ ) , ............ 1,0649 3,7210 4.9748 231 -9 236-9 241 -3 244.3 220-2 281'4 299'8 Freundler, it is well known, found that in a number of substances normal molecular weight in solution was accompanied by normal rota- tion, abnormal molecular weight by abnormal rotation. Patterson (Zoc. cit.) has shown, however, in the case of ethyl tartrate in various solvents, that normal molecular weight may coexist with abnormal rotation, and our observations furnish various instances of the same kind. The rotations of the three dimethoxysuccinates are consider- ably raised by benzene, and that of the methyl ester lowered by water, but the molecular weights are normal in these solvents so farROTATORY POWER.979 as the freezing point method can detect. Water increases the rotation of methyl tartrate by about ten times the value of the constant of the pure compound, but the molecular weight is nevertheless normal. The change here, it is true, may be due to depolymerisation, but the similar effect produced by water on the rotation of propyl tartrate cannot be thus explained, as there is no reason t o believe that this ester in the pure state is associated. Ethyl tartrate in a 5 per cent. benzene solution presents an exception to Freundler’s rule of another kind, for nearly normal rotation is here associated with distinctly abnormd molecular weight.The molecular weight determinations given above, and those by Freundler (Zoc. cit.), show that the tartrates, owing, no doubt, to the presence of the hydroxyl group, are subject t o extensive molecular association, even in comparatively dilute benzene solutions, and %hat in the alkylated esters this tendency to association entirely disappears. If molecular association is a predominant factor in the changes of rotation produced by solution, it should be clearly manifested in the rotations of the two closely-related classes of esters in the solvent mentioned. Such, however,-is not the case. The rotations of the dimethoxysuccinates, as already mentioned, are considerably increased by benzene, and those of the tartrates are modified in a manner that cannot be accounted for by the simple aggregation of active molecules as they exist in the pure liquid compounds, Methyl tartrate in benz- ene (Freundler, Zoc.cit.) exhibits extensive association accompanied by depression of rotation, propyl tartrate (see our tables) association accompanied by rise of rotation, and ethyl tartrate association, increasing rapidly with concentration, accompanied by only slightly changed rotation, which varies little with concentration. The coalescence of the active molecules of the ethyl ester evidently pro- duces little or no effect on their state of dissymmetry; it is natural to conclude that the same holds true for the molecules of its two homo- logues, and that the reversed effect of benzene on the rotations of the methyl and propyl esters is due mainly to an initial specific action of the solvent on the state of dissymmetry of the simple molecules of the compounds. Patterson, in the suggestive paper already referred to, has attempted, with some considerable success, to trace a connection between the influence cjf solvents on rotation and the internal pressure of the liquids, and more particularly between rotation and molecular solution- volume, which, on the assumption that the change of volume on solu- tion is suffered entirely by the dissolved substance, may be regarded as a measure of the pressure in question.Our observations are not extensive enough, and so far as the densities of the more dilute sola- tions are concerned, probably not accurate enough, to be employed as980 PURDIE AND BARBOUR: INFLUENCE OF SOLVENTS ON in any sense a crucial test of this theory; we have, however, calcu- lated the molecular solution volumes by the usual formula, when densities were available (see the Tables, pp. 973-975), to ascertain if the results gave any support or otherwise t o his views. For ethyl tartrate, to which so far his observations have been confined, Patterson finds that the values of the rotations in aqueous and different alcoholic solvents at infinite dilution stand in the inverse order of the molecular solution-volumes ; further, that solvents, such as methyl alcohol, which raise the rotation on solution, lower t8he molecular volume below that of the pure compound, whilst octyl alcohol, which causes a distinct fall of the rotation, raises the molecular volume.2limethoxysuccinutes.-The rotations of the methyl and ethyl esters are both lowered by methyl alcohol, as already stated, but the former decidedly more than the latter, while that of the propyl ester is only slightly affected. The molecular solution-volumes in this solvent are less than the molecular volumes of the pure esters. Benzene raises the rotations of all three esters considerably, but influences the mole- cular volumes very slightly. As exact data for the pure methyl ester at 20" are not available, in order to ascertain if any connection can be traced between rotation and molecular solution-volume in this group, we have compared the effects produced on the two constants by methyl alcohol and benzene respectively.We give below the differences be- tween the molecular rotation and molecular solution-volume of each ester in the two solvents in about 10 per cent. solutions a t 20". Diff. [M ];O". Diff. M.S,V. Methyl ester ............... 579" 7.7" Ethyl ,, ............... 39.2 3.6 Propyl ,, ............... 43.2 2.6 These figures certainly indicate a connection between the constants. The methyl ester, which shows the greatest difference of rotation, also gives the greatest difference of molecular solution-volume. The differ- ences of molecular solution-volume exhibited by the ethyl and propyl esters, it is true, do not stand in the same numerical order as the rota- tions, but the respective data for each ester approximate closely to each other, and the apparent discrepancy may well be due to slight error in determining the densities.Our observations on the methyl ester in methyl alcohol at varying concentrations appear also to indicate a connection between the con- stants in question. The rotations and molecular solution-volumes vary in the same order, each showing a minimum at the 10 per cent. solu- tion, but me do not attach great significance to this, as the range of concentration in the solutions is not sufficiently great, and the propyl ester does not show a corresponding regularity.ROTATORY POWER. 981 l'urtrates.-We have refrained from proceeding further with observ- ations on tliese substances, as we wished to avoid trespassing on Mr. Patterson's field of work. The following conclusions may, however, be drawn from the observations made, The effects of solution in water on the rotations and molecular solution-volumes of methyl and propyl tartrates correspond with those found by Patterson for ethyl tartrate, namely, a notable increase of rotation and decrease' of volume, but as will be seen from the numbers below, which refer to 5 per cent.solutions a t 20°, no connection between the two classes of effects is apparent. Increase of [ M 11. Decrease of M. V. Methyl tartrate ............ 31.9" 7.7" Ethyl ,, ............ 35.2 11.9 Propyl ,, ............ 33.6 14.6 The rotation of ethyl tartrate is slightly lowered by benzene, that of propyl tartrate much raised, but no corresponding change of molecular volume is evident ; as in the case of ethyl tartrate in octyl alcohol, the molecular solution volumes are greater than the molecular volumes of the pure liquids, and increase with dilution.Conzpcwison of Etlql Tcwlrccte and EthyZ Dimethoxysucciizccte. Below, we give the changes of rotation and molecular volume pro- duced by solution of these esters in methyl alcohol and in benzene at a concentration of about 5 per cent. and a t 20'; numerical rise and fall are indicated by the signs + and - rcspectively. Change of [MI:*". Change of 1I.V. Ethyl tartrate in methyl alcohol *... ......... + 7.9" - 11.5' ,, dimethoxysuccinate in methyl alcohol - 4.9 - 4.7 Ethyl tartrate in benzene ..................... - 1.8 + 4.1 ,, dimethoxysuccinate in benzene ...... + 35.6 unaltered The rotation of ethyl tartrate is more raised by methyl alcohol than that of the dimethoxysuccinate is lowered, and in agreement with this the tartrate shows a greater change of molecular volume.I n benzene, the tartrate also shows the greater change of molecular volume, but the effects on rotation, it will be seen, are in entire disagreement with this. The facts given above furnish no clear evidence of a definite connec- tion between rotation and molecular solution-volume, and we doubt if any such connection will be found to prevail generally. Patterson has pointed out several disturbing factors, which might account for the * Pattersoil (Zoc. dt.). trot. LXXIX. 3 x982 THORPE AND HOLMES: THE OCCURRENCE OF apparently abnormal relations between rotation and molecular solution- volume which he eccountered in some of his solutions. Another dis- turbing phenomenon suggests itself t o us, which may be of frequent occurrence. Patterson’s theory is based on the idea that a progressive change in the volume of an asymmetric molecule will be accompanied by a corresponding progressive change of shape, and therefore also of rotation. According t o Guye and Crum Brown, a continuous change in the value of one of the four coefficients of the groups attached to the asymmetric carbon atom, such as occurs in ascending a homologous series, may cause the rotation to oscillate between maxima on either side of the zero point. When the volume: and therefore the shape, of an asymmetric molecule is altered by the action of a solvent, no doubt the value of all four co- efficients will undergo change, but one of these will probably be more subject to the action than the others. A progressive change of mole- cular volume, whether caused by change of concentration or by the action of a succession of different solvents, might therefore result in a periodic change of rotation. This may possibly account for what seems to be a common phenomenon, the occurrence, namely, of a point of minimum rotation in the concentration-curves of solutions of active compounds, We doubt if this will be generally the case. UNITED COLLEGE OF ST. SALVATOR AND ST. LEONARD, UNIVERSITY OF ST. ANDREWS.

ISSN:0368-1645    

DOI:10.1039/CT9017900971

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

982 THORPE AND HOLMES: THE OCCURRENCE OF By T. E. THORPE, C.B., F.R.S., and JOHN HOLMES. BY the Act of 5 & 6 Vict., c. 93 (1842), manufacturers were permitted to use oil in making up spun or roll tobacco, and by the Act of 42 and 43 Vict., c. 21 (1879), the word ‘‘ oil ” is defined as meaning “ essential oil ” for the purpose of flavouring, and ‘‘ olive oil ” for ‘‘ the process of spinning and rolling up.” Prior to 1900, no legal prohibition existed as to the amount of “oil” which could be so used, but in that year it was found desirable to restrict the quantity which might be present in manufactured tobacco t o 4 per cent., and by 63 & 64 Vict., c. 35 (1 goo), i t was enacted that in calculating the proportion of oil, any fatty o r oily substance which may be naturally present in the tobacco is t o be included within the 4 per cent.Discussion with manufacturers prior to the introduction of thisPARAFFINS IN THE LEAF OF TOEACC‘O. 983 measure showed that it was necessary to obtain some definite know- ledge concerning L L the fatty or oily substance ” which was alleged to be present in the natural leaf of tobacco. It was surmised by some makers that tobacco leaf not only contained such substances, but that the quantity varied with the character of leaf, conditions of growth, season, &c. At the same time, no very precise information as t o the real nature of this so-called fatty or oily substance could be elicited, nor could auything relative to the subject be discovered in the already very extensive literature dealing with the natural history of tobacco.A rapid and sufficiently accurate method of ascertaining whether the provisons of the lam are complied with as regards oil consists in macerating a weighed quantity of the manufactured product with a definite volume of light petroleum, of boiling point not exceeding 60°, for about 18 hours at the ordinary temperature. An aliquot portion of the clear solution is evaporated and the residual extractive mat.ter is dried and weighed. This is then saponified with a solution of alcoholic potash and the equivalent amount of olive oil calculated from the saponification value. Direct experiments have shown that the whole of the added oil can in this may be readily estimated, and t h a t the results are not materially affected by the small amount of matter which the light petroleum may have extracted from the leaf.It was, however, desirable t o obtain accurate knowledge of the nature and amount of the substance or substances which light petrol- eum would extract from the natural leaf of tobacco. ,4ccordingly, quantities of the various kinds of leaf used by a number of the largest manufacturers in the United Kingdom in making spun or twist tobacco were procured for examination. The samples selected consisted of some 46 representative varieties of Kentucky and Virginian-grown tobaccos, and care was taken that they corresponded in all respects with the leaf as imported; in other words, it, was ensured that the tobacco was in the condition technically known as ‘‘ raw leaf.” The amount of matter extracted from tobacco by light petroleum a t the ordinary temperature is very small, even after prolonged macera- tion.I n the case of the American tobaccos above-named, i t varied from less than 0.5 up to about 2 per cent.; the average amount yielded by the 46 different varieties was 1.25 per cent. No glyceride, or anything in the nature of a vegetable oil or true fat, could be discovered in the extract. Hence the apprehensions of certain manufacturers t>hat their legal position might be prejudicially affected by the variable amount of fatty or oily matter occurring in the untreated leaf of tobacco had no foundation infact, since such substances are not naturally present in 3 x 2984 THORPE AND HOLMES: THE OCCURRENCE OF tobacco. Experience has, in fact, amply demonstrated that the limit of oil imposed by Parliament has proved more than suficient for the proper manufacture of spun tobacco.The matter extracted by light petroleum from tobacco constitutes a dark brown, viscous or semi-solid substance, I t is readily soluble in cold ether, carbon disulphide, chloroform, or carbon tetrachloride, but more sparingly so in absolute alcohol. On shaking with water, the aqueous solution is strongly alkaline, contains nitrogen, and gives the usual reactions for alkaloids with iodine, corrosive sublimate, and platinum tetrachloride. This alkaloid consists almost entirely of nicotine. It is present to the extent of about one-fifth of the weight of the extract. In addition, there is a small amount of wax, equal to about three-tenths of a per cent., on the original leaf, and, lastly, there are two solid hydrocarbons of the paraffin series, an account of which forms the subject of the present communication, I n order to isolate the paraffins, a quantity of the light petroleum extract obtained from several kilograms of Western Kentucky leaf, used mainly as ‘‘ fillers,” was dissolved in the minimum quantity of ethyl ether and the solution mixed with about six times its volume of ethyl alcohol (rectified spirit).The precipitate thus obtained was re- dissolved in hot alcohol, separated by cooling, and recrystallised from ether. It formed pearly, nacreous scales melting at 63*0-63.8’, and gave, on analysis, Carbon ....................... S4.9 per cent. Hydrogen .................. 14.7 99.6 - showing that i t was almost certainly a hydrocarbon, or mixture of hydrocarbons.That it was not a wax or solid fat was further established by boiling with standard solution of alcoholic potash. This was shown to have no action upon it, nor was the melting point of the substance at all changed. A second preparation, from another variety of tobacco used for ‘‘ wrappers,” and a third preparation from leaf employed for general purposes, gave very similar results on analysis, and the products had substantially the same melting point. The actual amount of the hydrocarbon present in the leaf seemed to be fairly constant, judging from the following results : (1) 34.92 grams of light petroleum extract obtained from 2.211 kilos. of Western Kentucky leaf gave 2.337 grams of hydrocarbon, or 0.10 per cent.on the original leaf. (2) 28.03 grams of extract from 1.3’75 kilos. of Henderson tobacco gave 1.757 grams of hydrocarbon, or 0.13 per cent, on the original leaf,PARAFFINS IN THE LEAF OF TOBACCO. 085 (3) 106.02 grams of extract from 7.084 kilos. of leaf used for general purposes gave 8.157 grams of hydrocarbon, equal to 0.11 per cent. on the original leaf. The amount of the hydrocarbon present in American tobacco leaf may be taken therefore as rather more than one-tenth per cent. Although the light petroleum employed in these extractions boiled completely below 60° and left no solid residue on evaporation, it was desirable to prove that the paraffins obtained, which conceivably might exert even at 60' sufficient vapour pressure to distil over with the more volatile hydrocarbons, were not actually present in the light petroleum employed.Accordingly, about a kilogram of leaf was treated in precisely the same way with a mixture of chloroform and ether. A white substance was thus obtained resembling in all respects that extracted by the light petroleum. It melted at 64-66', and was found on analysis to have the percentage composition : Carbon ...................... 85.0 per cent. Hydrogen .................. 14.6 ,, - 99.6 Systematic examination of the product thus obtained showed that i t was in reality a mixture. By repeated fractional crystallisation from ether it was eventually resolved into two solid hydrocarbons, which, by analysis and treatment with bromine, were recognised as paraffins.The first hydrocarbon was found to melt a t 6'7.8-6S*5O, and gave on analysis the following numbers : Carbon ........................ S5.1 per cent. Hydrogen .................. 14.S ,, 99.9 A solution in carbon tetrachloride was unaffected (N/lO) in the same .solvent, and the substance characters of a hydrocarbon of the CnH271+2 series. by bromine had all the A determination of the molecular weight by the boiling point method, according t o Beckmann, using ether as a solvent, gave values varying from 412 to 419, which agree fairly well with that demanded by the formula C,,H,, (mol. wt. 436). Indeed there can be little doubt that this hydrocarbon is identical with Krafft's hentviacontane, C31H64, which has the melting point 68.1' (Ber., 1882, 15, 1687).The second hydrocarbon, after repeated crystallisation from ether, in which it is markedly more soluble than the other, was found t o melt constantly at 59-3-59.89 On analysis, it yielded :986 THE OCCURRENCE OF PARAFFINS Carbon ........................ Hydrogen .................. IN THE LEAF OF TOBACCO. 84.9 per cent. 14.8 ?, 99.7 It was entirely unaffected by a solution of bromine (N/lO) in carbon tetrachloride, and was in other respects very similar in char- acter to the hydrocarbon just described. A determination of molecular weight by Beckmann’s method gave somewhat higher values (433-440) than those obtained in the case of the other hydrocarbon, but the results of the analysis and the melting point indicate that the second hydrocarbon is in all probability heptcc- coscme, C27H56, the melting point of which was found by ICrafft to be The two paraffins appear to he present in tobacco leaf in about equal amounts and in the aggregate, as already stated, to the extent of about one part in a thousand.We incline to the opinion that the substance obtained by Kissling (Ber., 1883, 16, 2432), and regarded by him as a wax, was in reality a mixture of the two paraffin hydrocarbons just described. Kissling, who extracted the material by means of ether, found after repeated recrystallisation from alcohol that it formed a snow-white mass of satiny lustre melting at 6 3 O , and gave on analysis numbers agreeing withthose required for the formula C,OH,,oO,(C = 83.0, H = 13.8,O = 3.2 per cent.). It was present in Kentucky tobacco to the extent of 0.18 per cent. I n the course of an investigation on the constituents of tobacco smoke, Kissling also found a wax-like substance, similar in appearance to the so-called ‘( tobacco wax,” melting a t 64*5*, but which seemed on analysis to be a hydrocarbon coGtaining C = 84-7-85.5 and H = 14.63--15.16 per cent. There can be little doubt that the substances extracted by Kissling are identical, and that they were mixtures of the paraffin hydro- carbons hentriacontane and heptacosane described in the present communication. As present in Kentucky and Virginia leaf, we found such mixtures had the following melting points : 59.5O (ZOC. cit.). Western leaf .................. 63-0-63*S0 ‘‘ Wrappers ” .................. 63.5-64.0 ‘ I Fillers” ..................... 63.7-65-0 numbers almost identical with those observed by Kissling. TIIE GOVERNMENT LABORATORY. I,ONDON.

ISSN:0368-1645    

DOI:10.1039/CT9017900982

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

STUDIES IN THE CAMPHANE SERIES. PART IV. 987 CV.-Xtudies in the Ccmphane Series. Part IV. The Isomerism o f a-Henxoylcu?izpho~-. By MARTIN ONSLOW FORSTER. ON continuing the investigation of 1 -hydroxycamphene (this vol., p. 644), attention was directed at first t o its anomalous behaviour to- wards ferric chloride, copper acetate, and alkalis. As already men- tioned, the substance in question is insoluble in caustic alkalis, its alcoholic solution does not yield a precipitate v i t h copper acetate, and ferric chloride fails t o develop a coloration with it. This inertness differentiates it quite sharply from those hydroxy-compounds represent- ing enolic modifications of the ketonic esters studied by Claisen, W. Wislicenus, Schiff, and others, and a review of the publications of these authors at once suggested a reason for this deviation from an apparently established principle.Briefly stated, it seemed probable that the peculiarity is due t o the fact t h a t 1-hydroxycamphene is the first enolic modification derived from a ketone containing a single atom of oxygen. Claisen, for ex- ample (Annulen, 1896, 291, 25), has studied the beliaviour of benzoyl- diacetylmethane, C,H,*CO*CH(CO*CH,),, dibenzoylacetylmethane, CH,*CO*CH(CO*C,H,),, and tribenzoylmethane, CH(CO*C,H,),, sup- plementing the examination of these substances by an investigation of methenyl and hydroxymethylene derivatives of ethyl acetoacetate, acetylacetone, and ethyl malonate (Annalen, 1897, 297, 1). The con- tributions of W. Wislicenus (Annalen, 1896, 291, 147) to this subject include the esters of forniylphenylacetic acid, CHO*CH(C,H,)*CO,H, and the isomeric forms of dibenzoylmethane (Annulen, 1899,308, 219), whilst Schiff (Annulen, 1899, 309, 206) has dealt with the benzyl- idenebisacetylacetones, C,H,CH*[CH(CO*CH,),],, amongst many others of the class under consideration. It is unnecessary t o mention more compounds belonging to this category.They display one feature in common. In each case, a complex containing oxygen is attached to the carbon atom adjacent t o t h a t united with the critical oxygen atom; in other words, the enolic modification invariably has an acidic group associated with the carbon atom contiguous t o the one bearing the hydroxyl radicle. It is this condition which is not fulfilled in the case of l-hydroxy- camphene, that substance having a single hydrogen atom in place of the acidic group, CH Hg*C02Et C8H,4<&OH CH,* C* OH 1 -Hydroxycamphene.Enolic ethyl acetoacetate.98s FORSTER: STUDIES IN THE CAMPHANE SERIES. It appeared likely, therefore, that this might account for the singular behaviour of the substance, and with the object of putting this explanation to the proof, I attempted to prepare a-benzoylcam- H*UO*C H ' 5, expecting that 1-hydroxy-2-benzoylcam- phene, the enolic modification of a-benzoylcamphor, would be found to resemble typical enolic substances : 5 , C* GO C,H, H$*CO*C,H C*Hl*<&oH C,H,*C*OH 1 -H ydroxy-2-benzoylcamphene. Hy droxy benzylideneacetophenone. Before proceeding to describe the process by mliich the enolic modi- fication of a-benzoylcamphor has been obtained, it may be stated that the substance has all the properties usually associated with enolic compounds.It dissolves readily in alkalis, develops an intense purple coloration with ferric chloride, and yields a crystalline copper deriva- tive when treated with copper acetate. It seems reasonable to con- clude, therefore, that the anomalous behnviour of the enolic modifica- tion of camphor is due to the fact that no acidic group is combined with the atom of carbon adjoining the one to which the hydroxyl group is attached. A t the same time, i t is obvious that phenol and phenanthrone (Japp and Klingemann, Trans., 1893,63, 770) cannot owe their acidity to an acyl group; in the case of these compounds, the existence of neighbouring unsaturated linkings must be held to exert a modifying effect on their properties (compare Thiele, Annalen, 1899, 306, 87).The method which has been adopted for preparing the enolic modi- fication of a-benzoylcamphor depends on the fact, first observed by Haller, that when sodium is dissolved in a solution of camphor in toluene, the sodium derivative of the ketone is produced. On treating this compound with benzoyl chloride, I obtained a dibenzoyl derivative which, judging by the behaviour of ethyl sodioacctoacetate under similar circumstances, might be expected to have one benzoyl group attached to carbon, whilst the other is united with oxygen, C CO C,H, c8H14<3.0. GO. C,H, 1 -Benzoxy-2-benzoylcaniphene. CO,Et* E*CO*C,H5 CH, * C 0. CO C,H, Ethyl dibenzoylacetoacetate.This view of its constitution is supported by its behaviour on hydro- lysis, as it is resolved into benzoic acid and 1-hydroxy-2-benzoylcam- phene, the latter bearing the same relation to a-benzoylcamphor that ethyl hydroxycrotonate has to ethyl acetoacetate. CH*CO-C,H, C S H 1 4 < b ~ 1-Hydroxy -2-benzoylcamphene. a- Benzoylcsmplior.PART IV. THE ISOMERISM OF a-BENZOYLCAMPHOR. 989 Several interesting points have arisen from an examination of hydroxybenzoylcamphene. I n the first place, its conversion into a-benzoylcamphor is brought about quite readily by the influence of concentrated sulphuric acid, or by fusion. When the substance is dissolved in organic solvents, many specimens will slowly change spontaneously into the ketone, the alteration being stimulated by adding a small proportion of piperidine, or by exposure to sunlight.This accelerating influence of light on the isomeric change of an optically active substance was first noted in connection with +-nitro- camphane (Forster, Trans., 1900, 78, 253), and a similar effect has been since observed by Pope and Harvey (this vol., p. 82s) in connec- tion with the racemisation of benzylphenylallylmethylammonium iodide. The marked enolic character of hydroxybenzoylcamphene is shown by the formation of sodium, copper, and ferric derivatives, which have been obtained in crystals; the substance combines also with phenyl- carbimide, and is readily acetylated by acetic anhydride, Conversion into a-benzoylcamphor is most conveniently effected by the agency of boiling formic acid, whereby about one-half is transformed into the ketone, which, on crystallising the mixture from alcohol, separates almost entirely in the first fraction.aBenzoylcamphor changes very readily into the isomeride when dissolved in organic media, and fusion produces the same effect. Ex- cepting camphor, it is the first optically active substance occurring in both forms of which a description has been. placed on record, and i t has been possible therefore to follow the interconversion of these two isomerides in the polarimeter. It is then found that a-benzoylcamphor, having the specific rotatory power [a], + 125", when dissolved in chloroform, gradually increases in optical activity until about 216' is reached, when no further change takes place ; the hydroxy-modification, on the other hand, undergoes a diminution of specific rotatory power from [a], + 2 8 1 O to the maximum attained by the ketone.The point of equilibrium therefore represents the specific rotatory power of the mixed ketone and enol in a proportion of 3 : 4 approximately. The readiness with which a-benzoylcamphor becomes transformed into the isomeride is in marked contrast with the behaviour of cam- phor itself. So little tendency is there on the part of the unsubstituted ketone to change into 1-hydroxycamphene, that the production of 1-benzoxy-2-benzoylcamphene is practically the first direct proof that camphor is capable of acting in the isomeric form, and hydroxycam- phene itself has been isolated only by a circuitous process.This is in close agreement with the observation made by Claisen that, in nscend- ing the series comprising triacetylmethane, diacetylbenzoylmethane, acety ldi benzoy lmet h ane, and tri benzoy lmet han e, the disposition to990 FORSTER: STUDIES IN THE CAMPHANE SERIES. persist in the ketonic form increases; in other words, the more negative the character of the group replacing methylene hydrogen, the greater the tendency of the diketone to undergo enolisation. Before proceeding to the experimental portion of this paper, it is necessary to mention that when the enolic modification of benzoyl- camphor is benzoylated, the dibenzoyl derivative produced by the direct action of benzoyl chloride on sodium camphor is regenerated. This is of greater importance than may*ppear, a t first sight, to be the case, because it was possible that the alkali used in hydrolysing the di benzoyl compound would convert the freshly produced a-benzoyl- camphor into an enolic substance, isomeric with 1-hydroxy-2- benzoyl- camphene, If this mere the case, however, the original dibenzoyl derivative C:C(C,H,)*O*CO*C,H,, and it is co must have the constitution C,H,,< I scarcely conceivable that such a compound could be produced by the direct action of benzoyl chloride on the sodium derivative of camphor. Moreover: a compound of the type indicated mould be comparable with the dibenzoyl derivatives of 1 : 3-diketones (compare Claisen, Annalen, 1896, 281, 97), for example, the benzoyl derivative of acetyldibenzoyl- methane, (CGH,*CO),C:C(CH3)*O*CO*C6H5 ; such compounds, however, when heated with aniline, are resolved into benzoic acid and an anilide which, in the case quoted, has the formula (Cj,H,* CO) 2c(: C( CH,) *N H*C,H,, whereas 1 -benzoxy-%benzoylcamphene is merely hydrolysed to enolic a-benzoylcamphor, accompanied by benzanilide. The same effect is produced even more readily by phenylhydrazine, which is converted into the symmetrical benzoyl derivative, and concentrated sulphuric acid also resolves the dibenzoyl compound into benzoic acid and enolic a-benzoylcamphor, associated with a considerable proportion of the ketonic isorneride. The investigation of 1-hydroxy-2-benzoylcamphene and its derivatives is being continued, and changes depending on its unsaturated character will be described in a subsequent communication.I wish t o express my indebtedness to Mr. W. J. Pope for kindly undertaking the crystallographic examination of the isomeric benzoyl- camphors.PART IV. THE ISOMERTSICI OF a-RENZOYLCAMPHOR. 991 E x P E R I 31 EN T A L. A solution of 150 grams of camphor in 400 grams of toluene wis heated with 15 grams of sodium in a reflux apparatus on the water- bath until the metal had completely dissolved. The liquid was trans- ferred to a wide-mouthed, cylindrical specimen jar, of about 1000 C.C. capacity, and the operation having been repeated, the united solutions were allowed to remain in the stoppered vessel during 24 hours. The dark brown liquid mas then decanted from the crystalline deposit, which mas broken up as ynickly as possible, and covered with a fresh quantity of toluene.The contents of the j a r having been thoroughly cooled by immersion in melting ice, benzoyl chloride was added in small quantities at a time, care being taken to prevent the action being confined to one portion of the material. Much heat was generated a t first, but subsequently it became possible to add the chloride in quantities of 10 or 15 grams. When 50 grams had beeti used for every 100 grams of camphor, the product, which had set to a jelly-like mass, was allowed to remain in ice during 1 hour, then mixed with its own bulk of water, and transferred to a large separating funnel, in which it was washed three times with water, and finally dried with calcium chloride. The toluene mas boiled away until a thermo- meter in the vapour indicated 140°, when the liquid, which had the odour of benzoyl chloride and camphor, was transferred t o a beaker, and heated in boiling water unt.il the greater portion of the camphor had been removed.Half its own bulk of alcohol was then added, and the crystals which separated during the following 24 hours mere filtered, washed, and recrystnllised from hot alcohol. A further quantity of the substance was obtained from the dark yellow, alcoholic mother liquor of tbe first crop by distilling it in a current of steam until all camphor and ethyl benzoate had been removed, and then add- ing half its own bulk of alcohol. The total yield amounted to 8 or 10 per cent. of the camphor employed. On analysis : 0,1784 gave 0.5182 CO, and 0.1074 H,O.C = 79.22 ; H= 6.69. 0.1660 ,, 0.4836 CO, :, 0.0989 H,O. C = '79.45 ; H = 6.62. C,4H,,0, requires C = SO.00 ; H = 6-66 per cent. Benzoxybenzoylcaniphene is sparingly soluble in cold alcohol, and crystallises from the hot solution in transparent, highly refractive, four-sided prisms melting at 144'; it is insoluble in water, but dissolves very readily in chloroform, acetone, ethyl acetate, ether,992 FORSTER : STUDIES IN THE CAMPHANE SERIES, Grams of Gram of benzene. substmce. _ _ ______--- pyridine, or glacial acetic acid, crystallising slowly from the last- named solvent in beautiful prisms. It is moderately soluble in boiling petroleum, which deposits it in minute prisms. A solution containing 1.0016 grams in 25 C.C. of chloroform at 22' gave U, 15'9' in a 2-dcm.tube, whence the specific rotatory power [aID + 189.7' ; Om25O2 gram dissolved in 25 C.C. of absolute alcohol at 2 7 O gave aD 3'45' in the same tube, corresponding to [a], + 187.3'. The substance is odourless, and is not volatile in steam; the alcoholic solution gives no coloration with ferric chloride, and is indifferent towards ammoniacal silver nitrate. It is insoluble in aqueous caustic alkalis, but dissolves readily in concentrated sulphuric acid. A determination of the molecular weight in benzene gave the following results : Grams of substance in Depression of 100 grams of freezing point. dzi$t:. solvent. ~~ I . Moleculav weight of C,,H,*O, r= 360. 18 -0.54 O W 7 0 1.7558 0.278" 316 9 ) 1 0.3940 1 2.1823 1 1 314 ? P 0'5152 2'8536 316 Action of Aniline on, B~zoxybenxoylcamp~e~e.-On heating 3.6 grams of the dibenzoyl derivative with 1-6 grams (18 mols.) of aniline during 4 hours in boiling water, the substance dissolved slowly, and separated unchanged when the liquid cooled.Ten grams were there- fore heated with 6 grams (2 mols.) of aniline at 110-120' during 12 hours ; the liquid solidified almost immediately on being withdrawn from the oven, and when quite cold the crystals were drained on porous earthenware, treated with a very small quantity of cold alcohol, again drained, and dissolved in 20 C.C. of boiling alcohol. As soon as the liquid was cold, the crystals were filtered washed, and recrystal- lised from hot alcohol, which deposited lustrous plates consisting of benzanilide, and melting at 161'.The first mother liquor, on standing during several hours, deposited the characteristic crystals of l-hydroxy- 2-benzoylcamphene. Action, of PhenyUiydrazine on Ben2oxybelzxoylcamp~ene.-The di- benzoyl derivative was heated with phenylhydrazine (2 mols.) in boiling water during 4 hours. The substance dissolved rapidly, and within less than an hour the liquid was filled with long, slender needles, When cold, the crystals were drained on porous earthenware, andPART IV. THE ISOMERISM OF a-BENZOYLCAMPHOR. 993 extracted several times with cold ether. The residue crystallised from alcohol in lustrous, flat needles, consisting of symmetrical benzoyl- phenylhydrazine, and the ethereal solution, on evaporation, deposited 1-h ydroxy-2-benzoylcmphene. Action of concentrated Suij~huric Acid on Benxoxy6enxoylcamphene.- Fifty grams of the finely powdered dibenzoyl derivative were added to 250 C.C.of ice-cold, concentrated sulphuric acid. After an interval of 1 hour, the pale yellow solution was poured on crushed ice, which pre- cipitated a sticky solid j this soon became crystalline, and was then filtered, washed, and treated with excess of an aqueous solution of sodium bicarbonate in order to remove benzoic acid. The undissolved portion was filtered, drained, and fused in 50 C.C. of hot alcohol, which was rapidly cooled. The product, weighing 35 grams, was recrystal- lised twice from small quantities of hot alcohol, and a t this stage began to soften a t about SOo, melted somewhat indefinitely a t 86 86", and gave [aJD +222O in chloroform.On dissolving 15 grams OF the material in 75 grams of hot absolute alcohol and allowiag the liquid t o cool in a 6-inch crystallising dish, two forms of crystals were dis- tinguishable, clusters of colourless needles, and isolated, flattened octahedra, which were distinctly pink ; these were separated mechanic- ally, weighing 4 grams and 8 grams respectively, the deposit from the mother liquor consisting of the octahedral form exclusively. The two modifications were then recrystallised separately from alcohol until the melting point was constant. The needles, which gave no immediate coloration with ferric chloride, melted at 87-88'. On analysis : 0.1270 gave 0.3682 GO, and 0.0920 H,O. A solution containing 0.6973 gram in 25 C.C. of chloroform a t 21" gave aD 7'8' in a 2-dcm.tube, whence the specific rotatory power [ The octahedra, on the other hand, developed an intense purple coloration when the alcoholic solution was treated with ferric chloride, and melted at 8 9 O . C = 79.07 ; H = 8.05. + 127.9'. On analysis : 0.1532 gave 0.4461 CO, and Od1O7O H,O. A solution containing 0.5272 gram in 25 C.C. of chloroform a t 20° The needles and octahedra were subsequently recognised as the C = 79.41 ; H = 7.76. C,7HzoOz requires C = 79.68 ; H = 7'81 per cent. gave uD 17'30' in a 3-dcm. tube, corresponding to [ a ] , + 276.69 keton:c and enolic modifications respectively of a-benzoylcamphor,994 FORSTER: STUDIES IN THE CAMPHANE SERIES. Fifty grams of the dibenzoyl derivative were dissolved in 500 C.C. of boiling alcohol, and heated in a reflux apparatus with 20 grams (24 mols.) of caustic potash dissolved in the minimum quantity of water.After 2 hours, the alcohol was distilled off, the residue was dissolved in water, heated on the water-bath until no alcohol remained, and diluted to 1000 C.C. with water. A current of well-washed carbon dioxide was then passed through the liquid, and when no further pre- cipitation occurred, the colourless product, which weighed 35 grams, was filtered, washed, and dried. On recrystallising the substance from 200 C.C. of absolute alcohol, a single compound was obtained in pale pink, flattened octahedra melting at 89'. The needles accompanying hydroxy benzoylcamphene when prepared by the action of concentrated sulphuric acid on the dibenzoyl compound, were, on this occasion, absent.When analysed : 0,1569 gave 0.4571 CO, and 0.1108 H,O. C,7H,00, requires C = 79.69 ; H = 7.81 per cent. A solution cont,aining 1,0227 grams in 50 C.C. of chloroform at 21' gave aD 23'0' in a 4-dcm. tube, whence the specific rotatory power [.ID + 281.1'; this fell to [.ID 3- 216' during a few hours' exposure t o light. A solution, prepared by dissolving 0.2930 gram in 25 C.C. of absolute alcohol at 21", gave 6'7' in a 2-dcm. tube, corresponding to [.ID + 262.2'; after 3 hours' exposure ti0 sunlight, this had fallen to [.ID + 208'. Hydroxybenzoylcamphene dissolves readily in hot alcohol, and crys- tallises in colourless, lustrous, transparent octahedra ; the first crop consists of pink crystals, the mother liquor depositing colourless ones, but no difference between them has been recognised besides a greater tendency on the part of the pink crystals, when dissolved, to change into the ketonic modification spontaneously.This change is dealt with in detail below. The substance is insoluble in water, but dissolves very freely in organic media. It is slowly soluble in aqueous sodium carbonate, but readily so in concentrated sulphuric acid. It is odourless, and is not volatile in steam. The alcoholic solution develops immediately an intense purple coloration with aqueous or ethereal ferric chloride, Mr. Pope has examined the crystals of this substance, and reports as follows : c c The crystals present the habit of square plates with one pair of C=79*45 ; H=7.84.PART IV. THE ISOMEltISM OF a-BENZOYLCAMPHOR. 995 opposite corners replaced, of tetrahedra with the edges replaced, or of flattened octahedra, according t o the relation in size between the forms n(100) and o ( l l 1 ) .These two forms are usually dominant, but occasionally the dome ~(101) is well developed; the form ~(110) is always small, and p’( 120) is only observed as a minute replacement of an edge or corner. The most usual habit assumed by the crystals is shown in Fig. 1. Owing t o the brittle nature of the crystals, sections could not be cut for optical exsmi nation. The form q(O11) is rarely observed, FIG. 1. (‘ Crgstalline system.-Orthorllornhic: : Sphenoidal Hemihedrism. : b : c = 0.9728 : 1 : 036550. “Forms observed : cc(lOO}, y(120)., p’flao), p{Oll), ~ { 1 0 1 ] , and “ The following angular measurements mere obtained : 0 + k { l l l } .Angle. np = l o o : 110 np‘ = 100 : 120 p’p’= 120 : 120 pp’ =110 : 120 a0 =100:111 0y =111 : 021 00 -111:111 up =111:110 ru =101:111 ar = l o o : A01 T?’ = 101 : 101 p?” =110 : 101 qq =011:01J qq = 0 1 ~ : 0 1 1 po =011:111 op’ =111 : 120 7’2 = l o 1 : 011 YJ(j’ =110 : OLl Number of ~ileasurei~ieiits. 24 38 1 6 22 43 19 20 11 1 5 47 26 18 19 14 7 12 16 9 Limits. 43’29’- 45” 1‘ G 1 5 7 - 63 25 63 4 5 - 55 11 1s 2 - 19 7 GG 4 - 61 36 28 57- 30 1 4 85 49 - 87 12 46 3 - 4 7 3s 27 4 6 - 29 0 5*5 I S - 66 53 67 12 - 68 2 ; 45 18 - 46 57 65 4 8 - 67 1 66 50- 68 5 65 49- 67 9 11240-114 ’7 48 46 - 50 16 6s 5 4 - i O 12 hl ea 11 observed. 44”lS’ 63 48 54 19 18 40 GO 4 1 99 40 S6 34 46 59 2S 1 7 56 3 67 56 16 7 66 1 9 67 38 66 29 113 26 69 4 i 49 58 Calculated.44”13’ 54 24 18 35 ti0 57 29 23 86 25 46 4 7 i 28 31 6 i 5-1 46 4 66 24 67 32 66 27 113 33 69 38 49 32 ” - -996 FORSTER: STUDIES IN THE CAMP HANE SERIES. The sodium derivative of hydroxybenzoylcamphene was prepared by adding 0.5 gram of sodium dissolved in alcohol to a solution of 2.5 grams of the substance in cold alcohol, and allowing the pale yellow liquid to remain in the desiccator. After an interval of a few days, the crystals, which were of moderate size but somewhat indefinite in struc- ture, were washed with alcohol and dried in the desiccator. On analysis : C,,H,,O,Na requires Na = 8-27 per cent. 0.2208 gave 0.0590 Na,SO,. The compound is readily soluble in alcohol and in water, which forms a strongly alkaline solution, dissociating when boiled.A solu- tion containing 0.5787 gram in 25 C.C. of absolute alcohol gave uD 13'20' in a 3-dcm. tube, whence the specific rotatory power [a], + 192.0'; this value points to almost complete dissociation having occurred, for in that case the substance would give [.ID 4- 190*5', assuming that transformation into the equilibrium mixture immediately followed dissociation. The copper derivative, obtained by adding 1.8 grams (4 mol.) of copper acetate dissolved in the minimum qtiantity of boiling alcohol to a solution containing 5.1 grams of hydroxybenzoylcamphene in 20 C.C. of absolute alcohol, crystallises in lustrous, sage-green needles. 0.1895 gave 0.0248 CiiO. Cu = 10.46. (CllH,,O,),Cu requires Cu = 11.07 per cent.The substance is insoluble in water, even on boiling, but dissolves sparingly in petroleum; it is very readily soluble in benzene, chloro- form, or nitrobenzene, forming brownish-green solutions. Acetone, which dissolves it very readily, yields a pure green solution, which also results from dissolving it -in ethyl or methyl alcohol ; the last- named solvent dissolves it but sparingly, even when boiled, depositing it in minute, green needles as the liquid cools. It is moderately soluble in ether, which yields a green solution, The ferric derivative was formed on adding to a solution of 2.5 grams of the hydroxy-compound in ether 0.6 gram (4 mol.) of ferric chloride dissolved in alcohol, followed by 0*8 gram (1 mol.) of sodium acetate in water, The liquid which remained after two days' exposure to air was decanted, and the crystals were drained on porous earthenware, and washed several times with water, and finally with dilute alcohol.The product has the colour of potassium permanganate. 011961 gave 0.0171 Fe20,. Fe = 6'10. (C,,H1,O,),Fe requires Fe * 6%2 per cent, The substance is quite insoluble in water, but dissolves freely in petroleum, chloroform, ether, alcohol, acetone, or nitrobenzene, forming solutions having the colour of port, Na = 8.65.PART IV. THE ISOMERISM OF a-BENZOYLCAMPHOR. 997 Efect of Heat on Hydroxybenxoylcamphne.-A specimen of hydroxy- benzoylcamphene giving [aID + 281O in chloroform was heated at the temperature ol boiling water during 4 hours. The substance solidified on cooling, and then gave [a$, + 267O in the same solvent.It there- fore changes into the equilibrium mixture less rapidly than the ketonic modification. Action of concentrated Sulphuric Acid on H2/drox~benxo?/lcn~~hene.- Single crystals of the hydroxy-compound giving [a], + 281' were powdered and dissolved in 4 parts of concentrated sulphuric acid. After 48 hours, the solution was poured on crushed ice, and the sticky pre- cipitate, when crystalline, was filtered, washed, and recrystallised from alcohol ; this deposited crystals among which both modifications could be recognised easily. Regeneration of the Dibenxoyl Derivative from Hydroxgbenxoyl- camphene. -Three grams of the hydroxy-compound were dissolved in 3 grams (3 mols.) of pyridine in a wide-mouthed stoppered bottle, and cooled by immersion in melting ice; 2-8 grams (2 mols.) of benzoyl chloride were then added drop by drop.After 3 days, the semi-solid product was treated with ether, filtered, and washed with ether. On evaporating the filtrate and distilling off the pyridine, the residue, consisting of the impure dibenzoyl derivative, became crystalline on cooling. The yield, including 0.5 gram obtained on dissolving out the pyridine hydrochloride with water, amounted to 3.5 grams. The mixture gave [aID + 211' in chloroform. CH*CO*C,H, a-Benxoylcamphw, C,H,,<&-, Ten grams of 1-hydroxy-2-benzoylcamphene were heated in a reflux apparatus with 40 grams of boiling formic acid (sp. gr. 1.2) during 4 hours, The liquid was poured into a large volume of cold water, which precipitated a colourless oil ; this solidified almost immediately when scratched with a glass rod, and was then filtered, washed, and dissolved quickly in 30 C.C.of absolute alcohol. This solution was immersed in cold water, and, after half an hour, filtered as rapidly as possible, because the filtrate began to deposit a mixture of both modi- fications when agitated, The needles obtained in this way consisted solely of the ketonic form, and amounted to 4.5 grams. Recrystallised from alcohol, they formed colourlees prisms melting a t 87-88', and gave no immediate coloration with ferric chloride. On analysis : 0.1645 gave 0.4792 CO, and 0.1144 H,O. CI7H,,O, requires C = 79.69 ; H = 7.81 per cent. A solution containing 0.5 gram dissolved in 25 C.C. of chloroform at 21° gave uI) 5'0' in a 2-dcm.tube if examined without any delay, whence the specific rotatory power [a]= + 185.0" ; 0.25 gram dis- C = 79-45 ; H= 7.72. VOL. LXXIX. 3 Y998 FORSTER: STUDIES IN THE CAMPHANE SERIES. solved in 25 C.C. of absolute alcohol at 21' gave aD 2'45' in the same tube, correHponding to [a J D + 137.5O. The substance is moderately soluble in methyl or ethyl alcohol, and dissolves very freely in benzene, ether, acetone, or chloroform; i t is only moderately soluble in boiling petroleum, which dissolves the enolic modification very readily. An alcoholic solution gives no imme- diate coloration with ferric chloride. The crystals of this substance have been examined by Mr. Pope, who reports as follows : (' The crystals are long, colourless, transparent needles of calcite-like lustre.The predominant form is the prism p(llO), and the crystals are elongated in the direction of the c-axis ; the dome q(011) is small, and the form q'(012) occurs as a minute replacement of the edge 011 : Oil (Fig. 2). The crystals are very brittle, and the optic axial plane is ~(001). I n the absence of pyramid forms or characteristic etch-figures, i t is impossible to say whether the crystals are or are not sphenoidally hemihedral. '' Crystalline system. - Orthorhombic, a: b : c = 0.7375 : 1 : 1.0224. (' Forms observed : p(110), q(O11), q'(012). FIG. 2. Q The following angular measurements were obtained : Angle. pp = i i o : i i o pp =110:110 pq =110 : 011 pq =110 : O i l pq = 0 1 1 : 0 ~ 1 qq =011:012 qf?f = 012 : 012 Limits.Number of measurements. 15 19 1 4 7 23 18 7 106'32'--107'56' 72 4- 73 52 64 7- 65 28 114 42-115 50 90 34- 92 2 53 26 - 54 47 18 1 - 1869 Mean. l07"lS' 72 49 64 45 115 21 91 16 54 6 18 34 107'11' 64 54 116 6 64 9 18 364 " - -PART IV. THE ISOMERISM O F a-BENZOYLCAMPHOR, 999 Efect of Heat on a-b;enxoylcamphor,-A specimen giving [ a ] D + 128' in chloroform was heated at the temperature of boiling water during 4 hours. The product remained superfused, but solidified rapidly when sown with a single crystal of the original substance. A determination of the specific rotatory power in chloroform gave [ a ] D + 231°, and on allowing the solution to evaporate spontaneously, and recrystallising the residue from a small quantity of alcohol, the first crop of crystals consisted exclusively of the enolic form.Interconversion of the Isomeric Benxoy~cccnaphors. Reference has been made t o the fact that certain specimens of 1-hydroxy-2-benzoylcttmphene, when dissolved in chloroform, sponta- neously undergo diminution in rotatory power, owing to gradual conversion into the ket,onic isomeride. If the change is allowed t o proceed, a point of equilibrium is reached when the specific rotatory power of the mixture is about [a]L, + 216'. The interval which elapses before the rotatory power becomes constant is, in the case of a 2 per cent. solution, about 6 days, the curve associating rotation with time being hyperbolic. On exposing a freshly prepared solution to sun- light, the rapidity of the change becomes greatly exaggerated, the position of equilibrium being reached in 2 or 3 hours.These remarks do not apply t o the colourless crystals of hydroxybenzoylcarnphene, a solution in chloroform having been preserved in darkness during 12 hours, exposed to bright sunlight during 2 hours, and even sown with a crystal of the ketonic isomeride, without suffering any perceptible reduction in optical activity. It appears, therefore, that some exciting agent is required to initiate the change, but i t is noteworthy that the ketone, so far as can beascertained, is more sensitive in this respect than the isomeride. As in former cases, piperidine has been observed to exert a stimu- lating effect on the interconversion of the two modifications. A 2 per cent. solution of the colourless hydroxy-compound, giving [ aIu + 2S0.4', was treated with 0-2 per cent.of piperidine ; after three-quarters of an hour, during which period the solution was protected from light, the specific rotatory power had fallen to [a], + 220'. Advantage has been taken of this action to compare the rates of speed a t which the two modifications approach the position of equilibrium, the result of the comparison being represented in the curve on p. 1000. From this it appears that, although the change from ketone t o enol takes place more readily than in the converse direction, the latter modification, when started, reaches the position of equilibrium much more rapidly than the ketone. 3 ~ 21000 FORSTER: STUDIES IN THE CAMPHANE SERIES. Action of Ferric Cldoride on the IgorneTic Be.nxoylcamphor8.As already stated, the enolic modification of a-benzoylcamphor, unlike the enolic modification of camphor itself, develops immediately lnlcrcoiwcrsion of the two ismneridcs iir a chloroform solution containing 0.05 per cent. of pipoerirlina. + 270" + 240° 4- 210" + 180" + 150" 4- 120" 0 30 60 90 120 minutes. an intense purple coloration with ferric chloride dissolved in water or inether. This is due to the formation of the ferric derivative,PART IV. THE ISOMERISM OF U-BENZOYLCAMPHOR. 1001 (C17H,,02),Fe, but it is highly probable that in absence of sodium acetate, such derivatives as C,~Hl,O2FeCl2 and (U17Hl,0,),FeC1 are produced at the same time, because the first-named compound has been isolated, and its solutions in organic solvents are found to be wine red, lacking the blue shade which the purple coloration exhibits.Moreover, when a very dilute solution of the enolic derivative in alcohol is treated with a single drop of a moderately concentrated aqueous solution of ferric chloride, a blue coloration is developed, and can be changed to the characteristic wine red shade of dissolved (CI7Hl,O2),Fe by adding aqueous sodium acetate (compare W. Wislicenus, Anncclen, 1896, 291, 173). The production of the purple coloration has been observed when ethereal ferric chloride is added to the enolic modification dissolved in benzene, ether, acetone, chloroform, methyl alcohol, or ethyl alcohol ; it is also developed when aqueous ferric chloride is added to an alcoholic solution of the substance, but a solution in chloroform re- mains colourless.The ketonic modification, dissolved in methyl or ethyl alcohol, gives no immediate coloration with an aqueous solution of ferric chloride, but in a few seconds the yellow solution deepens in colour, becoming greenish-brown, and then very deep green ; finally, after an interval of many minutes, the liquid acquires the purple tinge developed by the enolic modification, The same remarks apply when ethereal ferric chloride is employed, the changes in this case being more rapid. Solutions in acetone and ether give the green coloration almost imme- diately with ethereal ferric chloride, and quickly reach the bluish- violet stage. When chloroform or benzene is employed to dissolve the ketone, ferric chloride in ether produces an immediate green colwation, which rapidly becomes bluish-violet.In the case of benzene and ether, the final coloration is exactly the same as that developed by the enolic modification itself. Phenytwethane Derivative of l-~~ydroxy-~-benxoytcamptiene, The union of hydroxy benzoylcamphene with phenylcarbimide takes place very slowly. Five grams of the finely powdered hydroxy-corn- pound were placed in a stoppered weighing bottle, and covered with 3 grams of phenylcarbimide. After an interval of 7 days, during which the vessel was kept in a desiccator, the contents had changed to a bard, crystalline cake, which, when drained on porous earthen- ware, weighed 6 grams. As an alcoholic solution still developed an intense coloration with ferric chloride, the product was heated on the1002 STUDIES IN THE CAMPHANE SERIES.PART IV. water-bath with a small quantity of alcohol, cooled, filtered, and washed with cold alcohol until the washings remained indifferent to an ethereal solution of ferric chloride. The residue was then dissolved in 50 grams of boiling alcohol, which deposited minute, transparent crystals melting a t 117'. 0.1264 gave 0.3568 GO, and 0,0785 H,O. C24H250RN requires C= 76.80 ; H = 6.66 per cent. A solution containing 0.4913 gram in 25 C.C. of chloroform at 21' gave uD 7'30' in a 2-dcm. tube, whence the specific rotatory power [ u]; + 190.8'. The phenylurethane derivative is moderately soluble in alcohol and ether, dissolving very freely in chloroform. Alcoholic solutions are indifferent towards aqueous and ethereal ferric chloride. C = 76.98 ; H= 6.90. C*CO*C,H, 1-Acetoxy -2- benxoylcamphene, C8H, 4<e.o. co. H, Fifteen grams of 1-hydroxy-2-benzoylcamphene were heated in a reflux apparatus with 50 grams of boiling acetic anhydride during 3 hours. On pouring the liquid into a considerable volume of cold water, the derivative began to crystallise before the anhydride was nearly decomposed, and after an interval, was collected, washed, and recrystallised twice from alcohol. It separates from that solvent in long, lustrous, rectangular plates, and melts at 107'. 0.1760 gave 0.4912 CO, and 0.1170 H,O. C,,H,,O, requires C = 76.51 ; H = 7-38 per cent. A solution containing 0.5003 gram in 25 C.C. of chloroform a t 21°, gave uD 7'45' in a 2-dcm. tube, whence the specific rotatory power [ u ] ~ + 193.6' ; 0-2522 gram dissolved in 25 C.C. of absolute alcohol at 21' gave uD 3'48' in the same tube, corresponding to [a], + 188.3'. The substance dissolves freely in hot alcohol, but is only moderately soluble in the cold medium, It is also readily soluble in chloroform, ethyl acetate, glacial acetic acid, or boiling petroleum, separating from the last-named solvent in the characteristic rectangular plates. I n its behaviour towards concentrated sulphuric acid, acetoxybenzoyl- camphene resembles the corresponding benzoxy-derivative ; i t dissolves in the agent without rise of temperature, becoming converted into a mixture of the two benzoylcamphors, in which the enolic modification preponderates. C = 76.12 ; H= 7.39. ROYAL COLLEGE OF SCIENCE, LONDON. SOUTH KENSINGTON, S. W.

ISSN:0368-1645    

DOI:10.1039/CT9017900987

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

STUDIES IN THE CAMYRANE SERIES. PART V. 1003 CVL-Studies in the Camphane Series, Paint I? Halogen Devivatives of p- Cymene fyom substituted Nit rocamphanes. By MARTIN ONSLOW FORSTER and WILLIAN ROBERTSON, A.R.C.S. IT has been'mentioned that when 1 : l-bromonitrocamphane is dissolved in concentrated sulpburic acid, the anhydride, C,,H,,ONBr, is always accompanied by a viscous oil having a fragrant odour (Forster, Trans., 1899, 75,1145). Although the yield of this material does not exceed 10 per cent. of the halogen compound employed, an investigation of the anhydride and its derivatives has placed at our disposal a quantity sufficient for systematic examination ; this has been undertaken, therefore, in the hope that ideatification might afford some explana- tion of the obscure change taking place when 1 : l-bromonitrocam- phane is converted into the anhydride.Suspecting that the oil, which contains bromine, might arise from some impurity in the crude bromonitrocamphane, we ascertained that it is also produced when the material is recrystallised from acetic acid previous to dissolution in sulphuric acid, Moreover, a similar com- pound, containing chlorine in place of bromine, attends the conversion of 1 : l-chloronitrocamphnne into the anhydride, and consequently that substance has been included in the investigation. From this, we have ascertained that the oils in question are halogen derivatives of p-cymene, in which substitution has occurred in the ortho-position relatively to the methyl group. This result is noteworthy in being the second established instance of the production of substituted cymenes from camphor derivatives of known constitution.The transformation of camphor itself into cymene has been the subject of numerous investigations, but the first record of the observation of this change in derivatives of camphor occurs in a paper by Marsh and Hartridge (Trans., 1898, 73, 852), who found that on preparing carvenone by the action of concentrated sulphuric acid on 1 : l-dichlorocamphane, the product is contaminated with a small proportion of a chloro-derivative, which they believed to be chlorocymene [Me : C1: PrS = 1 : 2 : 41 ; the formation of this compound is not recorded by Bredt (Anncden, 1901, 314, 369), who repeated the experiments of Marsh and Hartridge. It will be noticed that the position of the halogen atom as regards the methyl and isopropyl groups is in complete agreement with the requii*ements of Bredt's formula for camphor, assuming no alteration to have taken place in the attachment of the bromine or chlorine.1004 FORSTER AND ROBERTSON : Klr CH,-YH-CH, CH,-CMe-CBr *NO, 1 : 1-Rromonitrocamphane.Bromo-p-cymene. \/ I YMe2 I -+ CH3 It is scarcely possible, however, to furnish an explanation of the change so simple as that given by Bredt (Zoc. cit.) for the conversion of cam- phor into cymene. Most likely the nitro-group plays an important part in the reaction, as the liberation of nitrous fumes has been observed during the production of the substance. In this connection, it is noteworthy t h a t 1-nitrocamphane does not yield cymene when dissolved in cold concentrated sulphuric acid, and appears to be quite indifferent towards that agent.Bromocymene [OH, : Br : G,H,P = 1 : 2 : 4 J from 1 : l-Brornonitrocm&zne. The accumulated bye-product from 500 grams of bromonitrocam- phane was washed several times with concentrated sulphuric acid, treated with water and dilute sodium carbonate, extracted with ether, dried with calcium chloride, and freed from ether, which deposited 50 grams of a pale brown, somewhat viscous oil, having a powerful, fragrant odour. We have not succeeded in isolating from this pro- duct a pure specimen of bromocymene, but there is every probability that the latter forms the chief constituent of the mixture. The fol- lowing evidence, coupled with the fact that 1 : 1-chloronitrocamphane yields chlorocymene under similar conditions, led to this conclusion.After the separation described above, the oil was distilled in steam, which separated i t from a less volatile, resinous material. A t this stage, it was optically active, giving aD - 13'31' in a 2-dcm. tube, and contained 33 *3 per cent. of bromine ; the substance was saturated, and did not contain nitrogen. It was then agitated with concentrated sulphuric acid, and after remaining in contact with that agent during some days was washed with sodium carbonate and distilled in an atmosphere of steam. The pale yellow oil decomposed when distilled under atmospheric presmre, evolving hydrogen bromide and becoming charred, It was, therefore, distilled under 26 mm. pressure, the major portion boiling at T28-130°, and then redistilled under the same reduced pressure, the final product boiling a t 129-130° ; although a mobile, colourless oil, the substance became pale yellow on exposure to sunlight.On analysis : 0.1614 gave 0.3230 CO, and 0.0888 H20. C = 54.58 ; H = 6.12. 0.2188 ,, 0.4361 CO, ,, 0.1216 H,O. C=54*35; Ht6917. 0.2509 ,, 0.2120 AgBr. Br = 35-95. CIoH,,Br requires C = 56.34 ; H = 6.10; BP = 37.56 per cent.STUDIES IN THE CAMPHANE SERIES. PART v. 1005 From these results, it appears that the bromocymene was still con- taminated with some oxygenated impurity, which is optically active, because the material analysed gave aD - 4'48' in a 2-dcm. tube. Such a substance could only arise by condensation of 2 mols. of bromonitro- camphane taking place according to the equation 2ClOHl,O2NBr - 2H20 - N20 = C2,H2,0Br,; a compound having this empirical formula would contain 54.0, 6.3, and 36.0 per cent.of carbon, hydrogen, and bromine respectively. These re- quirements mere so nearly met by our analyses, that a determination of the molecular weight of the substance in benzene was made. Molecular weight of ClOHI3Br, 213 ; C2,H,,0Er2, 444. Grams of benzene. 37-70 19.59 Grams of substance. 0.7082 0.1467 Grams of substance in 100 grams of benzene. 4.0011 0-7488 Depression of the freezing point. 0'938" 0.182 Molecular weight deduced. 213.3 215.4 This result pointed unquestionably to the substance being bromo- cymene, and was borne out by a determination of the density, which gave 1.257 at 16O, the value recorded by Landolph being 1.269 at 17-69 As it seemed likely that the oxygenated compound of the type indi- cated would be decomposed by alcoholic soda, the substance was sub- mitted to this treatment, because it is known that bromocymene is indifferent towards the agent in question.The resulting substance was almost colourless, and boiled at 2299 the temperature at which bromo- cgmene distils. On analysis : 0.1 836 gave 0.1588 AgBr. Rr = 36-82, CloHl,Br requires Br = 37.56 per cent. With the object of proving that this compound is derived from p-cymene, an attempt was made to reduce it in alcohol with sodium. Forty grams were dissolved in 300 C.C. of absolute alcohol, and heated in a reflux apparatus with 40 grams of sodium, which mas added in small quantities at a time, and soon gave rise to the separation of sodium bromide.When the metal had dissolved, water was added, and a current of steam was passed through the liquid until the alcohol had completely separated. On diluting the distillate with water, a colourless oil was precipitated, and this was collected, dried with1006 FORSTER AND ROBERTSON : calcium chloride, and distilled; i t boiled at 172' (uncorr.) under 770 mm. pressure. On analysis : 0.1226 gave 0.3990 00, and 0.1147 H,O. C,,H,, requires C = 89.54 ; H = 10.45 per cent, The identity of the hydrocarbon was placed beyond doubt by the operation recommended for this purpose by Widman ; oxidation with potassium permanganate in presence of caustic soda gave rise to a specimen of hydroxyisopropyl benzoic acid melting at 1579 C=88*76; H= 10.40.Anhydride of Cl~loronitrocu~phun~, CloH1,ONCI. In preparing the anhydride o€ chloronitrocamphane, it is of greater importance to keep the rise of temperature under control than even in the case of the corresponding bromo-derivative. One hundred grams of chloronitrocamphane were added in small quantities to 800 C.C. of concentrated sulphuric acid, cooled below 0' by a freezing mixture, and at no time was the temperature of the liquid allowed to rise above 5". The acid soon became dark brown, and a colourless, fragrant oil was produced, whilst towards the end of the operation hydrogen chloride was liberated. When all the chloronitrocamphane had been added, the liquid was allowed to remain in a separating funnel until the oil had risen to the surface, the acid being then run slowly on t o crushed ice; this precipitated a yellow solid, which was washed, drained on earthenware, and recrystallised twice from boiling alcohol.The yield under favourable circumstances amounts to 25 per cent. On analysis : 0.2345 gave 14.8 C.C. of nitrogen at 20° and 773 mm. N= 7.35. 0.2094 ,, 0.1521 AgCI. C1= 17.97. C,,H,,ONCl requires N = 7-02 ; C1= 17.79 per cent. The anhydride dissolves readily in hot alcohol, from which it crys- tallises in aggregates of opaque prisms; the melting point is not very definite, but the substance darkens above 200°, and melts at about 230' to a deep brown liquid which evolves gas. It is readily soluble in cold benzene and in ethyl acetate, crystallising from the latter in minute octahedra ; boiling water dissolves the compound very spar- ingly, but it is moderately soluble in boiling petroleum.Chlovocymerte [CH, : C1 : C,H,@ = 1 : 2 : 41 from 1 : 1-Chloronitrocclmphune. The oil referred to in describing the preparation of the anhydride of chloronitrocamphane waB decolorised by treatment with concentrated sulphuric acid, and washed with water, followed by sodium carbonate ; after being distilled in a current of steam, the product was collectedSTUDIES IN THE CAMPIIANE SERIES. PART V. 1007 Grams of benzene. with ether, dried with calcium chloride, and distilled, 26 grams being obtained from 300 grams of chloronitrocamphane. The substance obtained in this way was a colourless, mobile liquid boiling at 211-212O (uncorr.) under 768 mm.pressure; i t had a sp. gr. 1*0122 at 16', and although in these respects it agreed closely with pchlorocymene, the fact that it gave - 0'35' in a 2dcm. tube in- dicates that the substance was not quite pure. 0.1651 gave 0.4250 CO, and 0.1136 H,O. On analysis : C = 70-20; H=7.64. 0.2198 ,, 0,1863 AgC1. C1= 20.92. C,,H,,Cl requires C = 71.26 ; H = 7.72 ; C1= 21.02 per cent. A determination of the molecular weight in benzene gave the fol- lowing result : Molecular weight of CloH,,Cl, 168.5. Grams of substance Depression MoIecul ar of the of benzene. Grams cjf substance. in 100 grams freezing point. weight deduced. 25'03 $ 9 0'1358 0.5425 0.178" 152.4 0'2988 1 '1 938 0'380 157.1 Conversion of Chlovonitrocumphane Anlhydride into the Isomeride.Chloronitrocam phane anhydride was dissolved in 5 parts of alcohol and heated in a reflux apparatus with 2 parts of concentrated hydro- chloric acid during half an hour. The liquid was poured into cold water, and the precipitate crystallised from dilute alcohol, which deposits i t in needles. On analysis : 0.2038 gave 13.0 C.C. of nitrogen at 16O and 754 mm. 0.1500 ,, 0.1065 AgCl. C1= 17.56. C,,H,,ONCl requires N = 7.02 ; C1= 17-79 per cent. The substance is readily soluble in alcohol and is best recrystallised from boiling petroleum, in which it is only sparingly soluble ; it crys- tallises from the latter in transparent, six-sided plates, and melts a t 24SO. The benxoyl derivative, prepared by the Schotten-Baumann method, crystallises from alcohol in lustrous white leaflets, and melts at 166'.0.1546 gave 0.0712 AgCI. C1= 11.39. C17H,,0,NC1 requires Cl = 11 *69 per cent. N = 7.38.1008 FORSTEK AND ROBERTSON : Actim OJ HydroxyZamiw on th Anhydride of Chbrtitrommphane. Ten grams of chloronitrocamphane anhydride were dissolved in 50 C.C. of absolute alcohol, to which was added 8 grams of dry sodium carbonate. The mixture was then heated during 5 hours in a refiux apparatus with 10 grams of hydroxylamine hydrochloride dissolved in the minimum quantity of water. Alcohol was then distilled off on the water-bath, and the residue treated with a considerable quantity of water, filtered, and washed. The compound was recrystallised from alcohol, which deposited transparent, rectangular plates. 022951 gave 0.1805 AgC1. C1= 15.13.Cl,H170,N,CI requires C1= 15.27 per cent. melts a t 1 8 7 O , when it turns brown and evolves gas. ammoniacal silver nitrate readily on warming. which it crpstallises in lustrous, white needles, and melts at 1649 alcoholic solution is indifferent towards ammonincal silver nitrate. 0.2634 ,, 0.1625 AgCI. C1= 15.25. The hydroxylamino-derivative of chloronitrocamphane anhydride It reduces The benxoyl derivative dissolves somewhat sparingly in alcohol, from The Act$on of Nitric Acid on the Anhydrides of Bromonitrocamphane and Ch Zoronitrocarnphane. When the anhydride of bromonitrocamphane, obtained by dissolv- ing that substance in concentrated sulphuric acid, is treated with cold fuming nitric acid, it is dissolved immediately, and gas is liberated, but the diluted liquid does not yield a definite product.If, however, the isomeric anhydride is trwted in the same way, no change takes place, and the substance merely dissolves, but on heating the liquid a nitro-derivative is obtained. Ten grams of the isomeric anhydride were consequently heated with 40 C.C. of fuming nitric acid of sp. gr. 1.52 during several minutes, the liquid, when cold, being poured into a considerable volume of water, which precipitated a colourless oil. This solidified rapidly, and was then collected, washed, and crystallised from hot alcohol. On analysis : 0.2911 gave 25.1 C.C. of nitrogen at 17" and 763 mm. 0.3084 ,, 0.1997 AgBr. Brz27.56. The substance therefore appears to be a nitro-derivative. N= 10.23. C,,0,30,N2Br requires N = 9-69 ; Br = 27*68 per cent.It crys- tallises from alcohol in rosettes of transparent prisms melting at 103O, and is insoluble in sodium carbonate or caustic alkali. Unlike the substance from which it is derived, it gives Liebermann's reaction forSTUDIES IN THE CAMPHANE SERIES. PART V. 1009 nitroso-derivatives. Hot caustic soda decomposes it slowly, giving rise to infracampholenonitrile. The same difference in behaviour towards nitric acid is exhibited by the anhydrides of I : 1-chloronitrocamphane. Twenty-five grams of the isomeride melting at 248' were heated with 100 C.C. of fuming nitric acid during one minute only, the solu- tion being poured on crushed ice; the oil which separated soon solidi- fied, and was crystallised from alcohol, which deposited flat prisms resembling the corresponding bromo-derivative, and me1 ting at 7 1-72', 0.2204 gave 0.1309 AgCI.CI,H1,O,N,C1 requires C1= 14.53 per cent. The substance dissolves very readily in hot alcohol, and in cold benzene, ethyl acetate, or glacial acetic acid ; it is moderately soluble in boiling petroleum, from which it crystallises on cooling, and is also slightly soluble in boiling water. Decomposition with hot caustic soda is effected more readily than in the case of the corresponding bromo-derivative, infracampholenonitrile being produced. It gives Liebermann's reaction for nitroso-derivatives and does not reduce an ammoniacal solution of silver nitrate; it is distinguished from the original anhydride by indifference towards benzoyl chloride, which does not yield a derivative. Behaviour of the Nitro-compound on Reduction.-Ten grams of the nitro-derivative obtained from the isomeric anhydride of 1 : 1-chloro- nitrocarnphane were dissolved in 60 C.C. of glacial acetic acid, and treated with 20 grams of zinc dust. The metal was added in small quantities at a time, and the liquid was cooled after each treatment, but in spite of these precautions nitrous gases were liberated on each occasion. When all the zinc had been added, the product was allowed to remain at the ordinary temperature during 12 hours, then heated on the water-bath during 2 hours, and finally filtered. On diluting the acetic acid with water, a white, crystalline precipitate was obtained ; this weighed nearly 8 grams, and was readily identified as the anhydr- ide melting at 248'. The filtrate from this compound was rendered alkaline with caustic soda, and distilled in a current of steam, which carried over a small quantity of infracampholenonitrile ; the distillate was tested for hydrazine, but no reduction of ammoniacd silver nitrate occurred. From this experiment it appears probable that the nitro-groups in the derivatives of the anhydrides are attached to nitrogen. C1= 14-68. ~ Y A L COLLEGE OF SCIENCE, LONDON. SOUTH KLNSINGTON, S . W.

ISSN:0368-1645    

DOI:10.1039/CT9017901003

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

101 O JAPP AND MICHIE : REDUCTION OF Ur-DIBENZOYLPROPANE CVI1.-Reduction of a?-Dibenzoylpropane and Dibenzoyl- diphe92 ylbutudiene. By FRANCIS R. JAPP, F.R.S., and ARTHUR C. MICHIE, B.Sc. JOHANNES WISLICENUS has published, conjointly with some of his pupils (Annalen, 1898, 302, 191-244), a series of papers under the collective title, '' Formation of Carbocyclic Compounds by the Conversion of 1 : 5- and 1 : 6-Diketones into their Pinacones." Portions of the in- vestigation treat of matters which have already been dealt with by other methods in papers on the condensations of benzil with ketones published by one of us in conjunction with various collaborators ; but of the latter work, unfortunately everything except t h e first paper- " On Additive and Condensation Compounds of Diketones with Ketones " (Japp and Miller, Trans., 1885, 4'7, 11 ; also Re?*., 1885,18, 179)-has escaped the notice of the German investigators.The con- sequence is that they occasionally describe, as new, facts already known; that they fail to compare their compounds with others pre- viously described, even where this is of importance and that they sometimes misinterpret their results.. We have therefore subjected certain portions of their work to a careful revision. J. Wislicenus and C. K. Kuhn (Zoc. cit., p. 215) describe theprepar- ation of ay-dibenzoylpropane; its reduction, by the action of sodium on an ethereal solution of the substance floating on water, to an un- crystallisable oil which they regard as the cyclic pinacone 1 : 2-di- phenyl-1 : 2-dihydroxycyclopentane, the reaction taking place according t o the equation and, finally, the reduction of the latter compound by hydriodic acid to a substance which they regard as 1 : 2-diphenylcycZopentane, C,H,* QH-CH, C6H,.CH.CH2>CH2, a white, granular, crystalline mass melting a t 108'. These authors are apparently unaware that a substance claiming to be a 1 : 2-diphenylcyc2opentane (m. p. 47') has already been prepared. Japp and Burton (Trans., 1887, 51, 423), who obtained it by ths reduction of anhydracetonebenzil ( d ~ ~ ~ n y l c y c l o ~ ~ l e n o l o l z e ) , C,H,* C=CH C,H,. C(CH). cH2>C0, were uncertain whether it was a 1 : l-phenyl- benzylcpdobutape or a 1 : 2-diphenylcyclopentane, as the constitution of anhydracetonebenzil itself was not then settled, Japp and LanderAND DIBENZOYLDIPHENYLBUTADIENE.1011 (Trans,, 1897, 71, 128 and 131) conclusively showed that it had the latter constitution. Later on, we will briefly recapitulate their argu- ments, adding a further experimental proof. Our first impression was that the hydrocarbons melting at 47" and 108O respectively might be the cis- (meso) and the trans- (racemic) form. We therefore resolved to prepare the hydrocarbon melting a t 10s" by Wislicenus and Kuhn's method : in the first place, in order to com- pare the two compounds, and, secondly, to ascertain whether the hydro- carbon melting a t 47' was formed at the same time, as, i n the method of purification adopted by these authors, i t might possibly have been overlooked. We first prepared ay-dibenzoylpropane and, incidentally, greatly improved the yield of this substance by hydrolysing the dibenzoyl- glutaric ester with dilute sulphuric acid instead of with caustic alkali.The '( acid hydrolysis " of the ketonic ester obserqed by Wislicenus and Kuhn was thus entirely avoided, and only " ketonic hydrolysis " occ u wed, We then reduced the ay-dibenzoylpropane as prescribed by Wislicenus and Kuhn, and obtained the " pale-yellow oil " which they could not induce to crystallise, and which they therefore analysed Rfter leaving i t i n a vacuum desiccator until the weight was constant. They ob- tained figures agreeing with those required for the expected cyclic pinrtcone, 1 : 2-diphenyl-1 : 2-dihydroxycyclopen tam. We find, however, that, by appropriate treatment, no fewer than five distinct substances can be separated from this '' pale-yellow oil " : (1) the above cyclic pinacone (m.p. 103-1045"); (2) in small quantity, aE-diphenyl-ar-dibydroxypentane, C,H,* CH(OH)*CH,* CH,* CH,* CH(OH)*C,H5 (m. p. 84-88O), which we were afterwards able t o prepare in some- what larger quantity by reducing ay-dibenzoylpropane with sodium in boiling alcohol ; (3) a small quantity of unchanged ay-dibenzoylpro- pane, which is always present, even when the sodium in Wislicenus and Kuhn's method is used in the enormous excess of more than 20 times the theoretical amount; (4) a colourless oil, soluble in light petroleum, and (5) a yellow resin insoluble in light petroleum, That the pale-yellow oil " gave, in Wislicenus and Kuhn's hands, figures agreeing with those required for the pinacone, was therefore a pure coincidence.We found that the pinacone could be obtained much more readily, and in a state of purity, by reducing uy-dibenzoylpropane in hot aqueous alcoholic solution with aluminium amalgam. Chromium trioxide, in acetic acid solution, readily reconverts the pinacone into ay-dibenzoylpropne. As regards the hydrocarbon, we prepared it both according to1012 JAPP AND MICHIE : REDUCTION OF ay-DIBENZOYLFROPANE Wislicenus and Kuhn's directions from the '' pale-yellow oil," and afterwards from the pure pinacone. By their method of purification, one and the same substance, agreeing fairly well with their descrip- tion, was isolated in both cases, It is of very indefinite character and is certainly not a diphenylcyclopentane. Thus it does not boil even a t 340' under 12 mm.pressure, whereas 1 : 2-diphenylcyclopentane from anhydracetonebenzil boils quite constantly at 189' under 1 2 mm. pressure. Again, it must appear somewhat strange that Wislicenus and Kuhn's diphenylcyclopentane should melt as high as 108' and be practically insoluble in alcohol, seeing that Wislicenus and Carpenter's tetraphenylcyclopentane (Anmlen, 1898, 302, 229), in spite of its two additional phenyl groups, melts as low as 81O and is soluble in alcohol, We have therefore no hesitation in saying that Wislicenus and Kuhn's supposed 1 : 2-dipheny lcyclopentane is a highly polymerieed substance, and that the action of hydriodic acid on the pinacone is much less simple than these authors have assumed.Indeed, the known action of acids upon pinacones, in producing dehydration and migration, might have suggested the need for caution on this point. As it was apparently impossible to obtain 1 : 2-diphenylcyclopentane from the pinacone, it was of interest to ascertain whether the reverse change could be effected ; whether the known 1 : 2-diphenylcyclopentane (m. p. 47") from anhydracetonebenzil could be oxidised either to a pinacone-identical or stereoisomeric with that above described- or, failing this, to aydibenzoylpropane. We Found that the latter transformation readily takes place when the hydrocarbon is treated with chromium trioxide in acetic acid solution in the cold : C6H5*~H*CH2 C,H,* CO*CH C,H,* COO CH, C6H,*CH*CH2 1 : 2-Diphenylcyclopentane ay-Dibenzoylpropane.(m. p. 47"). PUH, + H,O. >CH, + 30 = All attempts to obtain an intermediate oxidation product proved fruitless. The foregoing reaction entirely confirms the constitution of a 1 : 2-di- phenylcyclopentane which Japp and Lander assigned to the hydrocarbon Cl,H18 (m. p. 47') from anhydracetonebenzil. Before leaving this part of the subject, we will arrange in their order the different compounds which have been obtained by one of us, conjointly wit.h pupils, in the transformation of b e n d and acetone, on the one hand, into ay-dibenzoylpropane, on the other : CH3>Co C,H,*YO C,H5*$!0 C,H, * CO + zE?co & C,H,*C(OH)*CH, Y Acetonebenzil (m. p. 78").AND DIBENZOYLDIPH&~NYI~BUTADIENE, 1013 C,H,* C===CH C,H,.#-CH2 -+ KOH CGH,d(OH)*CH2>co Hi C,H;C*CH, >co 3 Anhydracctonebenzil Diplienyle yclopentenone (m.p. 149”). ( I l l . p. 110”). The of its 1 : 2-Dipheaylcz~cZopeiitaiie ay-Dibcnzoylpropsne constitution of anhydracetouebenzil has been proved by a study reactions, too long to recapitulate here (compare Japp and ( I l l . 1’. 47”). (ni. p. 67.5”). Lander, Trans., 1897, 71, 123) ; that of diphenylcyclopentenone by it,s formation from anhydracetonebenzil, by its giving a phenylhydr- azone, and by its being oxidised quantitatively t o diphenylmaleic acid by sodium hypobromite (ibid., 132) ; and finally, that of 1 : Z-diphenyl- cyclopentane both by its formation from diphenylcyclopentenone by re- duction, and by its conversion into ay-dibenzoylpropane by oxidation, as also by the fact that it behaves as a saturated compound, both towards bromine and towards hydriodic acid at 150’ (Trans., 1887, 51, 424)” Wislicenus and Lehmann (Annalen, 1898, 302, 195) have studied t h e action of alcoholic sodium hydroxide and sodium ethoxide on a mixture of b e n d and acetophenone. By the first method they obtained a/3-dibenzoylphenylethylene (ap-dibenzoylcinnamene, anhydr- C,H,*$XCH*CO*C H acetophenonebeiizil),? 5 , which they recognised as CGH,*CO identical with the compound obtained by Japp and Miller by the action of warm aqueous potash on a mixture of b e n d and acetophenone (Trans., 1885, 47, 35).Wislicenus and Lehmann’s method, however, yields * It is not often that Dr. M. 11. Richter, the author of the invaluable Lexikon der Kohlenstof- Ve~bin&6~geen, ventures t o combine his already sufficiently arduous task of coinpilation with that of criticism.With regard to the present question, however, after accepting Wislicenus and Kulin’s compound a t their own valuation as (‘ 1,2-Diphenyl-R-Pentamethylen, Sni. lOS”,” he indicates his scepticism regarding the 1 : 2-diphenylcydopentane of ni. p. 4’1” by querying its constitution. Again, Richter-Anschutz’s O~gmzische Chcniic (9 th edition, 2, 10) gives only Wislicznus and Kuhn’s compound. The reasons for this preferential treatment of the non-existent 1 : 2-diphenylcyclo- pentane are assuredly not chc7nicnl. t I must, I think, decline the responsibility for some, at least, of the changes of name that this compound has undergone. The first systematic name assigned to it by Dr.Klingemann and niyself was “ afi-dibenzoylstyrolene,” and under this name it was described in the Proceedings (1889, 5, 136). On our sending the full paper to the Journal, Rlr. C. E. Groves, a t that time Editor, pointed out to us that the official name for “ styrolene ” was “ cinnamene,” and that, in any case, the coni- pound would be thus indexed. We therefore made the required change to “ afi-di- benzoylcinnamene” (compare Trans., 1890, 57, 662) ; but I now find that the compound appears in the Collective Index as “ aS-dibenzoylstyrene.”-F. R. J. VOL. 1LXXlX. 3 21014 JAPP AND MICHIE : REDUCTION OF a~-DIBENZOYLPROPANE the compound mixed with dibenzoyldiphenylbutadiene, and is there- fore inferior to that described by Japp and Klingemann (Trans., 1890, 57, 673), in which, by employing as a condensing agent alcoholic potassium hydroxide very slightly diluted with water, pure @-dibenzoyl- phenylethylene is obtained.Wislicenus and Lehmann have overlooked the lattor paper, with the result that, in addition to employing the foregoing unsuitable method of preparation, they make various deter- minations without indicating that these are merely confirmations of some already made : thus an ebullioscopic determination of the molecular weight, already determined cryoscopically by Japp and Klingemann (ibid., 674), and a few indications of the crystalline form (two angles measured), whereas Tutton (Trans., lS90, 57, 714) gives full crystallographical measurements of up-dibenzoylphenyl- ethylene and ten of its derivatives. If this mere all, the matter would not, of course, be worth calling attention to.But this want of acquaintance with the foregoing work causes the German authors to go somewhat astray in their interpretation of the chief reaction of their paper-the reduction of dibenzoyldiphenylbutadiene. Dibenzoyldiphenylbutadiene, which had not been previously prepared, was obtained by Wislicenus and Lehmann (Zoc. cit., 198) by the con- densation of 1 molecular proportion of beazil with 2 of acetophenone under the influence of alcoholic sodium ethoxide. They leave it an open question whether the compound has the symmetrical or the unsymmetrical constitution : C,H&:CH*CO*G,H5 C6H,C:CH*CO*C,H5 Or C6H,*Co CH* CO*C,H, They subjected this compound to the action of various reducing agents, and obtained various products.One of the latter, which was formed by reducing the substance with hydriodic acid in glacial acetic acid solution and boiling the resinous product with alcoholic potassium hydroxide, and to which the formula C,,H,,O is assigned, attracted our attention; partly because it was difficult to see how it could have such a formula, and partly because it was obviously identical with an already known compound of a different formula. The authors describe the substance as crystallking from alcohol in ‘‘ long, colourless, flat needles, melting at 92-94’.’’ They found benzoic acid in the alkaline solution from the treatment of the resin, and explain the formation of the compound as follows : ‘‘ By t.he action of the alkali, the resinous reduction product of the diketone-the latter a compound containing four phenyl groups-has been broken up into a molecule of benzoic acid and a cornpound, C,,H,,O, containing three pheny 1 groups.” Leaving difficulties with the hydrogen out cf the question, three phenyl groups would account for C18, leaving C, over for the grouping C,H,*v: CH* 8 c6H5AND DIBENZOYLDIPHENYLBUTADIENE.1015 of these three phenyl groups, and the authors refrain from hazarding any explanation as to how a dibenzoyldiphenylbutadiene, whether symmetrical or unsymmetrical, could yield a compound in which three phenyl groups are attached to the group C,. Speculation on this point is, however, unnecessary, inasmuch as the compound has not the formula C,,H,,O, but C,,HlsO (Wislicenus and Kuhn's figures agree, on the whole, rather better with this formula than with that which they calculate); and is identical with the sub- stance which Japp and Burton (Trans., lSS7,51, 430) obtained by the reduction of ap-dibenzoylphenylethylene with hydriodic acid.The latter authors describe the compound as forming '' colourless, long, flatlprisms melting constantly a t 92-93O," which agrees with Wislicenus and Lehmann's description. Japp and Klingemann (Bey., 1888,21,3933 ; Trans., 1890, 57, 663) showed later that the compound mas 2 : 3 : 5-tri- We therefore repeated the reduction of dibenzoyldiphenylbutadiene with hydriodic acid, as described by Wislicenus and Lehmann, omitting, however, the boiling with alcoholic potash, and, instead, distilling the product under reduced pressure. We thus obtained without difficulty metophenone and 2 : 3 : 5-trip~~en?/lfu~furc~n, tho formation of the former of which explains that of the latter. In the first stage of the reaction, the dibenzoyldiphenylbutadiene parts with one C,H,*CO*C)H group by hydrolysis as acetophenone, and the resulting ap-dibenzoylphenyl- ethylene is then reduced t o triphenylfurfursn.Assuming, for sirn- plicity, the symmetrical formula for dibenzoyldiphenylbutadiene, the process may be represented as follows : CBH5*$X CH CO*C,H, CGH5*C0 + C,H,*C'O*CH,. 0 2 : 3 : 5-Tripliciiylfurf~iran (In. p. 92-93"). The boiling with alcoholic potash employed by Wislicenus and Lehmann, has therefore nothing to do with the formation of' the triphenylfurfuran, although this treatment may, of course, have aided in removing impurities.3 z 21016 JAPP AND MICHIE : REDUCTION OF uy-DlBENZOYLPROPANE The various facts above referred to, which have escaped Wislicenus and Lehmann’s notice, are to be found collected together in Beilstein, 3, p. 308, in the article ‘‘ Dibenzoylstyrol,” EXPERIMENTAL. Prepcwation of Ethyl Dibenxoylglutarate ( EthyZ n~~t~&~ZenedibenxoyZ- C,H,*CO*~H.CH,*~H*~O*C H acetate), 5.-This substance was pre- CO,C,H, GO,* CzH5 pared by the condensation of formaldehyde with ethyl benzoylacetate as described by Knoevenagel (Annalen, 1894, 281, 57), except that we employed as a condensing agent piperidine instead of diethylamine.” One hundred and twenty grams of ethyl benzoylacetate and 24 grams of R 40 per cent.aqueous solution of formaldehyde mere mixed, and 15 grams of piperidine gradually added, cooling with water all the time. As soon as the liquid began to thicken, alcohol was added; this prevented the whole from setting to a hard cake, as in Knoevenagel’s experiment. The compound is deposited from the solution in a crystalline condition, and after recry stallisation from alcohol, forms colourless needles melting constantly at 92-5”, showing straight extinction in polarised light and giving no coloration with ferric chloride. (Knoevenagel gives the melting point as S6O, but he employed only 2 grams of ethyl beiizoyIacetate in the preparation of the substance, and the quantity obtained was probably insufficient for complete purification. He does not indicate the crystalline form.) The yield varied somewhat. The most favourable result was 100 gyams of once crystallised product from the foregoing quantities.Wislicenus and Kuhn (Annalen, 1898, 302, 215) prepared ethyl dibenzoylglutarate by the action of methylene diiodide on ethyl benzoylsodioacetate. I n this way, they obtained it as an uncrystallis- able oil, which gave a cherry-red coloration with ferric chloride.? I n one experiment, they obtained an isomeric ethyl dibenzoylglutarate melting a t 130.5’. Preparatioyz of ay-Bibeneoylpropane, C6H,* CO- CH,*CH,*CH,* CO*C,H,. -Wislicenus and Kuhn prepared this compound by boiling the 6‘ crude, oily ethyl dibenzoylglutarate ” with a 10 per cent. aqueous solution of potassium hydroxide for 9 hours, This process, however, yielded, along with the diketone, y-benzoylbutyric acid. I n order to * This was clone merely because we happened to have a stock of the former base.t his coloration may, of COIII’SC, have been due to an enolic form of ethyl Still, some proof of the absence of unchanged ethyl benzoyl- Ill many of these condensations, Knoevenagel uses either base indifferently. dihenzoy]glutarate. acetate from the uiicrystallisable oil would appear desirable.AND DlBENZOYLDIPHENYLBUTADIENE. 1017 avoid this '' acid hydrolysis," we hydrolysed the ester by boiling it with dilute sulphuric acid. Forty grams of crystallised ethyl dibenzoylglutarate were boiled for 2 hours with 200 C.C. of a mixture of equal volumes of concentrated sulphuric acid and water, using a reflux condenser.A more dilute acid does not produce hydrolysis, whilst one more concentrated corn- pletely resinifies the substance ; indeed, even with an acid of the fore- going strength there is a certain amount of resinification, the organic substance, which floats in a fused condition on the surface of the liquid, being reddish-brown at the end of the process, whilst the aqueous Iayer is highly fluorescent. The evolution of carbon dioxide is practically complete a t the end of the 2 hours, and longer boiling diminishes the yield. The flask was cooled with water, shaking all the time, and the product, which was thus obtained in a granular form, was separated, washed with water, dissolved in ether, and the ethereal solution mas shaken with sodium carbonate solution, dried with calcium chloride, and concentrated.The dibenzoylpropane was deposited in lustrous lamina+ a second crystallisstion sufficing to fur- nish a colourless product melting a t 67-5", as described by Wislicenns and Kuhn. From alcohol, it crystallises in blades ; from light petrol- eum, in which i t is only sparingly soluble, in very slender needles. The yield was 65 per cent. of the theoretical. Reduction of Dibenxo?~lpopccne in Btherecd solutbn wit?b Xodiunz .- The process of reduction was carried out exactly as prescribed by Wislicenus and Kuhn (Zoc. cit., 221). An ethereal solution of 10 grams of dibenzoylpropane was introduced into a flask along with water, and 40 grams of sodium in small pieces was gradually added, cooling all the time. (Wislicenus and Kuhn merely state that EL very large excess of sodium is to be employed, without specifying the amount.) The addition of the sodium took about 2 days.The ethereal solution was separated from the yellow, aqueons layer, dried with anhydrous sodium sulphate, and evaporated to expel the ether, after which i t was left in a vacuum desiccator over sulphuric acid for several days. It formed a pale yellow syrup, agreeing with the description given by Wislicenus and Kuhn, who analysed i t in this condition. As our final results in dealing with this substance differ very materially from those of Wislicenus and Kuhn, we venture to describe the method of purification more fully than mould otherwise be necessary. The syrupy substance was extracted with successive portions of boiling light petroleum (" ligroin "), using a reflux condenser ; it be- came crystalline on warming with the light petroleum, but the crystals afterwards melted again. After four extractions there remained only cz hard, yellow resin, insoluble in light petroleum.The four extracts,1018 JAPP AND MICHIE : REDUCTION OF a~-DIBENZOPLPROPANE which were kept separate, deposited on cooling a colourless oil, which on standing partly crystallised in short, thickish needles, which give a red coloration with concentrated sulphuric acid. The first extract yielded most crystals. The united mother liquors from these crops gave on concentration tufts of very slender needles, totally distinct from the others, After recrystallisation from light petroleum they melted at; 84-88', and when free from the thickish needles gave only a yellow coloration with sulphuric acid.They proved to be a€-di- p~enyl-uE-dil~~drox~penice described later on. The last mother liquor gave a small quantity of unaltered dibenzoylpropane. The purification of the substance crystallising in thickish needles was a matter of some difficulty owing to the oil with which they mere contaminated. In the case of the first crop some fairly pure substance was obtained by recrystallising from a mixture of benzene and light petroleum. The other portions were dissolved in boiling light petrol- eum, and the flask containing the decanted hot solution shaken under the tap until a portion of the oil had separated; the solution, again decanted from the oil, gave the short, thickish, prismatic needles.The various portions of crystalline substance obtained by these various methods mere finally united and recrystallised from light petroleum until they showed the constant melting point of 103-104*5". In polarised light, the needles shorn oblique extinction. They dissolve in concentrated sulphuric acid, giving a deep red, strongly fluorescent solution. Owing to loss in purification, the yield of pure substance was only 1.4 grams. Occasionally in the crystallisstion of the foregoing substance the tufts of slender needles (m. p. 84-SS0) made their appearance. These could be got rid of by pouring off the solution from the thickish needles before the others separated. After both kinds of crystals had been as far as possible removed, there remained a colourless oil which could not be made to crystallise by contact with any of the three crystalline substances isolated from the mixture.Analysis of the substance molting a t 103-104.5' gave figures agreeing with those required by the cyclic pinacone, 1 : 2-diphenyl-1 : 2- dihgdroxyc yclopentane, It mas not further examined. ~- - C,H,*y( OH) *CH C,H,* C(OH)*CH, 2>CH2. 0.1652 gave 0.4846 CO, and 0.1059 H,O. C = 80.00 ; H = 7.12. CI7H1,O2 requires C = 80.31 ; H = 7-08 per cent. Afterwards, when we had prepared the cyclic pinacone in quantity by the reduction of dibenzoylpropane with aluminium amalgam, we found that it was deposited from glacial acetic acid in crystals of theAND DIBENZOYLDIPHENYLBUTADIENE. 1019 formula C17H,,02,C2H,02 sparingly soluble in the cold acid.The pinacone should be dissolved in the glacial acetic acid with the aid of a gentle warmth, as heating with the acid turns it yellow, and decomposes it. In the form of this double compound the pinacone can, as the following experiment shows, be readily separated from the other substances formed in TNislicenus and Kuhn’s process of reduction. Ten grams of dibenzoylpropane in ethereal solution were again reduced with sodium as already described, but instead of treating the syrupy product with light petroleum, it was dissolved in a little more than its own bulk of glacial acetic acid. As i t showed no tendency t o crystallise, a small portion mas removed and frozen with ice and salt ; on allowing it to thaw, crystals of the double compound remained, and with these the crystallisation of the rest mas started.The sub- stance was deposited in large crystals; after expelling the acetic acid of crystallisation, the pinacone t h u s obtained weighed 3.7 grams, and, save for a very faint brownish tinge, was pure. After a second crys- tallisation from acetic acid, it was colourless. The crystals efloresce only very slowly a t the ordinary temperature. For analysis, they were dried by pressing between filter paper and then exposing to the air for two and a half hours. 0,8735 lost, on heating at 70°, 0.1688. C,pHls0,,C,H,02 requires C2H,02 = 19.10 per cent. The acetic acid mother liquor, separated from the first crop of crystals of the foregoing double compound and containing the re- mainder of the reduction product, yielded, by spontaneous evaporation, only a small quantity of the same crystals, imbedded, however, in a thick syrup which showed no tendency to crystallise.We estimate that the crude, syrupy reduction compound, analysed as the cyclic pinacone by Wislicenus and Kuhn, contains not more than 50 per cent. of that substance. Reduction of Dibernxoylpopane with Sodium in, boiling Alcohol.- Twenty grams of dibenzoylpropane were dissolved in absolute alcohol and 24 grams of sodium gradually added to the boiling solution. On diluting with water, an oil separated; this was taken up with ether, the ethereal solution dried with fused potassium carbonate, and the ether expelled on the water-bath. The yellow, oily product showed no tendency to crystallise, but by the following rather tedious process we succeeded in isolating a crystalline substance from it.The oil was dissolved in a moderate bulk of alcohol; the solution was diluted with an equal volume of water, shaken in a corked flask, and allowed to stand. As soon as the oil had settled, the solution, which was still somewhat turbid, was decanted into a beaker and again allowed to C,H,02 = 19-32.1020 JAPP AND MIOHIE : REDUCTION OF a~-DIBENZOYLPROYANE stand, so as to allow part of the alcohol to evaporate. More oil separ- ated, and the liquid, which had become clear, was again decanted and allowed to evaporate in a vacuum desiccator over sulphuric acid, when it deposited clear, prismatic crystals.* The oils mere redissolved in alcohol and again treated in the same way, repeating the process as often as crystals were obtained.The united crops of crystals were recrystallised, once from dilute alcohol by the same method, and then twice from light petroleum. From the latter solvent, the substance was deposited in very slender needles melting at 84-88', identical with those obtained in small quantity along with 1 : 2-diphengl-1 : 2- dihydroxycydopentane in the treatment of Wislicenus and Kuhn's reduction product with light petroleum. In the present case, if the crystallisation was allowed t o go on too long, a slight separation of the thickish, short needles of the cyclic pinacone from the light petr- oleum solution was observed, but by filtering as soon as the slender needles were deposited, the pinacone remained in the mother liquor.The new compound crystallises from dilute alcohol in lustrous, slender, six-sided prisms, from light petroleum in very slender needles, both showing straight extinction in polarised l.ight. The melting point is not sharp; the substance fuses between 84-88' t o a turbid liquid which clears at 92'. If free from the cyclic pinacone, it gives only a yellow coloration with concentrated sulphuric acid. Analysis gave figures agreeing with the formula of uc-diphenyZ-uc- dihydvoxypentane, C,H,* CH (OH)*CH,* CH,* CH,*CH( OH). C,H,. 0.1314 gave 0*3817 CO, and 0*0926 H,O. C = 79.22 ; H = 7.83. 0.1356 ,, 0.3953 CO, ), 0,0951 H20. C = 79.50 ; H= 7-79, C',,HzoO, requires C = 79.69 ; H = 7.81 per cent. The yield of pure substance from 20 grams of dibenzoylpropane was only 0.3 gram.Reduction Di6enxoylpropane 6y AZzcminim ArnaZgum.-This re- action furnishes the best means of obtaining 1 : 2-diphenyl-1 : 2-di- hydroxycylcopentane, but the success of the method depends on the observance of certain precautions. No reduction takes place in abso- lute alcohol; the best result was obtained with a solution in alcohol diluted with half its volume of water. The condition of the amalgam is important ; if it is allowed to heat up and oxidise during its prepara- tion, it becomes inert. Ten grams of aluminium powder, previously freed from oil by treat- ment with ether in a Soxhlet's extractor, was shaken for a few seconds with 10 C.C. of a saturated alcoholic solution of mercuric chloride * Sometimes an oil separates a t this point also, and does not crystallise until Once crystals have been obtained, it is better to start the The following method gave a good result, after long standing.crystallisation with nuclei of these.AND DIBENZOYLDIPHENYLBUTADIENE. 1021 which had been diluted with 100 C.C. of the same solvent, was then rapidly filtered through a disc of loose felt on a perforated porcelain funnel, using the filter pump, washed quickly with alcohol, and a t once transferred to a flask containing 10 grams of dibenzoylpropane, 200 C.C. of alcohol, and 100 C.C. of water. The flask was fitted with a condensing tube and was heated on a metal plate over the water-bath, repeating the heating every day for some time. At first the liquid deposited, on cooling overnight, blades of dibenzoylpropane, the quantity of which, however, daily diminished, until at last they ceased to appear.The reduction must, however, be carried considerably beyond this point. After a week, as the evolution of hydrogen had become very slow, a second portion of 10 grams of aluminium amalgam was added, and a third was sometimes found necessary a t the end of another week. From a fortnight to three weeks' heating was thus required according to the activity of the amalgam, and it was found that the addition of the latter in successive portions, as just described, gave a better result than when it was added all a t once. The filtered and concentrated solution ought to yield, on diluting slightly with water, needles of the cyclic pinacone, unmixed with the blades and lamins of unaltered dibenzoylpropane.If, however, the latter sub- stance is present, the mixture of crystals should be dissolved in a little glacial acetic acid with the aid of a gentle warmth; the liquid on standing deposits crystals of the cyclic pinacone containing acetic acid of crystallisation, whilst the dibenzoylpropane remains in solution. If it is necessary to concentrate this solution, i t should be done under diminished pressure, in order to avoid the decomposing action of the hot acid on the pinacone. If the reduction has been properly carried out, the yield is quanti- tative. The pinacone was deposited from dilute alcohol in thick needles. For analysis, it was recrystallised from light petroleum, from which it separated in short needles melting at 103-104.5°, identical with the compound of the same melting point obtained by the reduction of dibenzoylpropane with sodium in ethereal solution.Analysis gave figures agreeing with those required by 1 : 2-diphenyl-1 : 2-dihydi.oxy- c y clopent ane. 0,1816 gave 0.5340 GO, and 0.1190 H,O. C = 80.19 ; H= 7.28. 0.1511 ,, 0.4440 CO, ,, 0,0965 H,O. C=80*13 ; H=7.09. C17Hl,0, requires C = 80.31 ; H = 7-08. Stereoisomerides were not observed. Oxidation of 1 : 2-DibenxogZ-1 ; 2-diphenylcyclopentane lo ay-Dibenxoyl- popctme.-1'5 grams of the cyclic pinacone were dissolved in glacial acetic acid with the aid of a gentle warmth, and the same weight of1022 JAPP AND MICHIE : REDUCTION OF Uy-DIBEKZOYLPROPANE chromium trioxide, dissolved in the same menstruum, was gradually added. As no oxidation had taken place after standing for 20 hours in the cold, the mixture was warmed for a short time on the water- bath and then poured into water.Laminae of ay-dibenxoylpropane separated. After freeing from acid by means of sodium carbonate, an ethereal solution deposited crystals showing the melting point of ay-dibenzoylpropane (67.5") and indistinguishable from that substance. Reduction of 1 : 2-Di6enxoyl-l : 3-dipiien~lcyclopentane with Hydriodic Acid and Red Phosphorus.-This reduction was carried out exactly as described by Wislicenus and Kuhn, heating the cyclic pinacone with hydriodic acid and red phosphorus in sealed tubes a t 150-160". One set of experiments was performed with the crude syrupy pinacone, as prescribed by these authors. Afterwards we used the pure pinacone.Finally we tried the experiment, not mentioned by Wislicenus and Kuhn, of boiling dibenxoylpropune with hydriodic acid (sp. gr. 1.7) and red phosphorus for 13 hours. I n every case, by employing the method of purification prescribed by these authors-namely, of repeatedly dissolving the product of reduction in ether and precipitating it with alcohol-we obtained what appeared to be the same substance. It was a white, wax-like solid, which showed a tendency to become more granular by repeated precipi- tation and which finally melted at 105-108". It was readily soluble in ether and in benzene, practically insoluble in alcohol. I n these respects it agreed fairly well with the description of Wislicenus and Kuhn's hydrocarbon melting at 108'.We introduced a portion of this product (prepared from the syrupy pinacone) into a bulb which was exhausted by means of a filter-pump and then heated in a spermaceti-bath, the temperature being gradually raised to 340". At that temperature and under a pressure of 12 mm., there was a mere trace of a distillate, but the greater part of the sub- stance showed no sign of volatilising. The distillate did not crys- tallise. We had intended to make an ebullioscopic determination of the molecular weight of the substance, but after the result of the fore- going experiment, we did not regard this as necessary. The mole- cular weight was obviously very much higher than that of a diphenyl- cyclopentane-the substance which Wislicenus and Kuhn had supposed it to be. The mother liquors obtained in the purification of the foregoing sub- stance mere examined.By evaporating to dryness and distilling the residue under diminished pressure a crystalline substance was obtained, but in quantity too small for further examination. It was not identi- cal with Japp and Burton's 1 : 2-diphenylcyclopentane (m. p. 47O). The latter compound is not formed in t h i s reduction.AND DIBENZOYLDIPHENYLBUTADIENE. 1023 Boiling point of 1 : 2-Diphenylcyclopentane (m. p. 47') from Anhydr- cccetonc6enxiZ.-Japp and Burton (Trans., 1887, 51, 423) found that, under atmospheric pressure, this hydrocarbon boils, with partial decomposition, a t 3059 In order better to compare it with Wislicenus and Kuhn's supposed 1 : 2-diphenylcyclopentane, we determined its boiling point under reduced pressure.A well-crystallised specimen melting at 4 7 O was employed for the purpose. It passed over withoiit decomposition quite constantly a t 189' under 1 2 mm. pressure (tem- perature of oil-bath 200'). The colourless distillate solidified to a mass of white crystals of un'changed substance. Oxidcction of 1 : 2-Diphenylcyclopentane (m. p. 47').-0.6 gram of 1 : 2-diphenylcyclopentane (m. p. 47") was dissolved in glacial acetic acid, a solution of 1.2 grams of chromium trioxide in acetic acid mas gradually added, the mixture was allowed to stand for 20 hours, and poured into water, Solid caustic soda mas added so as to leave the liquid slightly acid, after which the solution was extracted with ether. The ethereal solution, after removing acids, deposited lamince of ay-dibenxoylp~opccne, which after recrystallisation showed the correct melting point of 67.5'.A supersaturated solution of the substance in alcohol at once crystallised on seeding it with a crystal of dibenzoyl- propane, Benzoic acid was also formed, together with a small quantity of an acid crystallising from water in minute prisms or needles melting a t 133*5O, which we were unable to identify. Reduction of Diphenyldibenxoylbutccdiene. -Five grams of diphenyl- dibenzoylbutadiene were boiled with 200 grams of glacial acetic acid, 10 grams of hydriodic acid (sp. gr. 1*7), and 2 grams of red phosphorus for 3& hours, employing a reflux condenser, The liquid was filtered, precipitated with water, and extracted with ether ; the ethereal solution was treated with sulphurous acid and sodium carbonate, dried with calcium chloride, and after expelling the ether, the residue was distilled under a pressure of 12 mm.Part passed over a t SO-%' ; it smelt of acetophenone, and when cooled in melting ice and touched with a small crystal of acetophenone, solidified. Nearly the whole of the residue distilled when the oil-bath was at 275-295". It was dissolved in alcohol. On cooling, an oil separated. The mother liquor was evaporated to a small bulk and crystallisation was started by seeding with 2 : 3 : 5-triphenylfurfuran. The oils were repeatedly boiled up with alcohol and the clear solutions obtained on cooling were treated in the same manner. I n this way, a relatively good yield of colourless needles was obtained. After recrystallisation they melted a t 92-93', were indistinguishable from crystals of S : 3 : 5-triphenyl- furfuran (m. p. 92-93') and, like these, showed straight extinction in polnrised light. Wislicenus and Lehmann obtained in the analysis1024 JAPP AND MELDRUM: of this substance : C = 88-85, H = 5-60 (mean of two analyses), the for- mula of triphenylfurfnran, C,,H,,O, requiring C = 89.1 9, H = 5.40. The formula C,,H,,O, calculated by Wislicenus and Lehmann, re- quires C = 88.88, H = 5.20, so that analysis alone is hztrdly competent to decide between the two formula. The proof of the correctness of the formula C,,H,,O is to be found in the fact that the same com- pound is formed in a quantitative yield by the reduction of ap-di- benzoylphenylethplene and by other methods which leave no doubt as to its constitution. The above experiment shows, moreover, that the treatment of the product of the reduction of diphenyldibenzoylbutadiene with alcoholic potash, which Wislicenus and Lehmann regarded as essential to the formation of the substance melting at 92-23'? was unnecessary. The chief products of the reduction of diphenyldi benzoylbutadiene in our experiment mere, therefore, acetophenone, formed by hydrolysis, and 2 : 3 : 5-tripherzylf2crfuiwccn, formed by the reduction of ap-dibenzoyl- phenylethylene, the other product of hydrolysis (see Introduction). The other compounds obtained .by Wislicenus and Lehmann may have been present in the residue, spnringly soluble in alcohol, which remained after the extraction of the triphenylfurfuran ; but we did not examine this further. CHEMICAL DEPARTMENT, UNIVERSITY OF ACERDEEN.

ISSN:0368-1645    

DOI:10.1039/CT9017901010

出版商:RSC    

年代:1901

数据来源: RSC