CONDENSATION OF PHENOLS WITH ESTERS. 1185 CXXV.-Conderzsation of Phenols with Esters of the Acetylene Swies. Part VI. By SIEGFRIED RUHEMANN and ERNEST WRAGG, B.A. PREVIOUS researches led to the result that ethyl acetylenedicarb- oxylate and ethyl chlorofumarate yield the same esters on treatment with the sodium phenolates, and that the acids formed from them on hydrolysis readily condense to derivatives of 1 : 4-benzopyrone under the influence of concentrated sulphuric acid. As has also been shown, the acids obtained from the products of the interaction of the sodium phenolates with ethyl phenylpropiolate cannot be thus transformed into flavone and its homologues, but on distillation lose carbon dioxide, yielding phenoxystyrene and its homologues, and on treatment with sulphuric acid decompose into carbon dioxide, acetophenoue, and the corresponding phenols.Similar is the behaviour of the substances produced from eugenol and m-xylenol, which is described in this paper. Although we have not been able to obtain the benzopyrone compound from eugenoxyfumaric acid, yet xylenoxyfumaric acid can readily be condensed to dimethyl- benzopyronecarboxylic acid. P-m-Xylenoxycinnamic acid, on the other hand, is completely decomposed by sulphuric acid. The fact that the aryl ethers of P-hydroxycinnamic acid are not transformed into benzopyrone derivatives induced us to ascertain whether this reaction is prevented from taking place only by the pre- sence of the phenyl group, or whether hydrocarbon radicles in general VOL. LXXIX. 4 M1186 RUHEMANN AND WRAGG : CONDENSATION OF PHENOLS have this effect.For this purpose, we have studied ethyl /3-phenoxy- crotonate, which is formed by the action of sodium phenolate on ethyl P-chlorocrotonate, and have found that the corresponding acid does not yield a benzopyrone compound, but undergoes changes similar to those observed in the case of the aryl ethers of P-hydroxycinnamic acid. On heating, it loses carbon dioxide and forms P-phenoxypropylene, thus : CH3*C(O*C6Hg):CH*C02H = CO, + CH,*C(O*C,H,):CH,, whilst under the influence of sulphuric acid it suffers the following decomposition : CH,~C(O*C,H,):CH*CO,H + H,O = CO, + CH3*CO*CH3 + C,H5*OH. With the view of testing whether the difference in the behaviour of the aryl ethers of /3-hydroxycinnamic and P-hydroxycrotonic acids from that of the ethers of hydroxyfumaric acid is caused by the con- figuration of the unsaturated acids, we have subjected /3-chloroiso- crotonic acid, instead of its stereoisomeride, to the action of sodium phenolate.We find, however, that the same compound is formed as when ethyl P-chlorocrotonate is used. This result may be explained by the assumption that the formation of ethyl P-phenoxycrotonate is preceded by the addition of sodium phenolate t o the chlorocrotonic esters, accompanied by the transformation of ethyl /3-chlorocrotonate into ethyl /3-isochlorocrotonate. The resulting substance would thus - . CH,=E*O*C H ', which on account of the CO,Et*C*H have the configuration 6 axial position of phenoxyl to the ester group could not yield a benzo- pyrone compound. EX PER^ MENTAL.The union of eugenol with ethyl chlorofumarate takes place when the unsaturated ester (1 mol,) is gradually added to a solution of sodium (1 at.) in an excess of the phenol. The dark, viscous product is heated for a short time, and, after standing for several hours, treated as in the former cases. The ester is a yellowish oil which boils at 231-232' under 14 mm. pressure ; it possesses an aromatic odour, and at 2l'/Zl' has the density 1-1 256. 0.2030 gave 0.4822 CO, and 0-124'7 H,O. On analysis : C = 64.73 ; H= 6.82. C,,H,,O, requires C = 64.67 ; H = 6-58 per cent. il I31 [41 Eugenosyficmaric Acid, C3H,(O*CH3)CGH3.0* C( C0,H): CH*CO,H. - The potassium salt of the acid separates as a crystalline solid on boil-WITH ESTERS OF THE ACETYLENE SERIES. PART VI.1187 ing the ester with alcoholic potash for 2--3 hours. After the product has been freed from alcohol by distillation on the water-bath, water is added to the residue, and the solution treated with an excess of dilute sulphuric acid, when the organic acid separates as an oil. This is prevented from solidifying on account of the presence of eugenol, which is formed along with eugenoxyfumaric acid on hydrolysis of the ester. In order t o remove the phenol, the ethereal solution of the oil is shaken with sodium carbonate, and an excess of dilute sulphuric acid added to the aqueous layer. The organic acid which separates is best extracted with ether, and, after complete evaporation of the latter, remains as a yellow solid, which is very soluble in ether or alcohol. It readily dissolves in boiling water, and, on cooling, crys- tallises in yellowish plates which melt and decompose a t 172-173', On analysis : 0.2142 gave 0.4755 CO, and 0.0980 H,O.C1,H,,OG requires C = 60.43 ; H = 5.03 per cent. Eugenoxyfumaric acid dissolves in concentrated sulphuric acid, forming a dark red solution. After standing overnight, it is gradually poured into cold water, when a brownish, gelatinous precipitate is produced, which we have been unable to obtain in a crystalline form, and therefore have not further examined. C = 60.54 ; I3 = 5-08. Action of the Xodium Derivative of m-Xy%nol on Ethyl Phen&ropiolale. Ethgt p-m-Xylenoxpcinnumate, The action of ethyl phenylpropiolate (1 ~nol.) on a hot solution of sodium (1 at.) in an excess of m-xylenol takes place very readily.The sodium derivative of the phenol, which parlly separates on adding the unsaturated ester, disappears. The dark red oil which is formed sets, on cooling, t o a resin. After standing for some hours, it is agitated with dilute sulphuric acid and ether ; the ethereal layer is then freed from the excess of the phenol by potash, the ether evaporated, and the remaining oil distilled in a vacuum. It boils a t 225-226' under 10 mm. pressure, is colourless, and at 2lo/2l0 has the density 1.0946. On analysis: 0.187'7 gave 0*5300 CO, and 0.1180 H,O. C = 77.0 ; H = 6.98. C11,H200, requires C = 77-02 ; H = 6.76 per cent. P-m-Xylenoxycinnamic Acid, (CH3)2C6H3*O*C(C6H5):CH=C02H.- The ester is hydrolysed when it is boiled with alcoholic potash for 2 hours. On adding dilute sulphuric acid to the alkaIine fluid after evaporation of the alcohol on the water-bath, @m-xylenoxycinnamic [1:3] 141 4 M 21188 RWHEMANN AND WRAGG : CONDEKSATION OF PHENOLS acid is precipitated a s a resin, which, on stirring with a little alcohol, sets to a solid.This dissolves in hot dilute alcohol, and the solution, on cooling, yields an emulsion from which colourless prisms gradually separate. On analysis : The acid melts a t 121-122O with evolution of gas. 0*2000 gave 0.5575 C0,and 0*1080 H,O. C = 76.02 ; H= 6.0. C,?H,GO, reqriires C = 76.12 ; H = 5.97 per cent. The siher salt is obtained as a white precipitate on mixing the solution of the acid in ammonia with silver nitrate; i t is neither changed on exposure to light nor decomposed on drying at 100'.On analysis : 0.2994 left, on ignition, 0.0858 Ag. Ag = 28.66. C,?H,,O, Ag requires Ag = 28-80 per cent. [1:3] [JI P-m-Xylenoxystyrene, (CH,),C,H,*O*C(C,H,) :CH2.-/3-m-Xylenoxy- cinnamic acid, on heating, loses carbon dioxide, and P-m-xylenoxy- styrene is formed, It is a colourless oil with a n aromatic odour, distils at 178' under 15 mm, pressure, and a t 3l0/2lo has the density 1.0353. On analysis ; 0.1700 gave 0.5343 CO, and 0.1090 H,O. C = 85-71 ; H = 7-12, C,GH,,O requires C = S5.71; H = 7.14 per cent. Action of the #odium Derivative of m-A7yZenol on Ethyl Chlorofumnrate. CH,/\CH, ~H.CO,*C,H,. Ethyl m-Xylernoxyfumarate, \/-O-C I 1 CO,-C,H, This compound is formed in a similar manner t o the other aryl ethers of ethyl hydroxyfumarate, that is, by graduaily adding ethyl chlorofumarate (1 mol.) to a hot solution of sodium (1 at.) in a n excess of m-xylenol.The dark product, after treatment as in the former cases, yields a yellowish oil which boils at 202-203° under 17 mm. pressure, and at 2lo/2lo has the density 1.0978. On analysis : 0.2033 gave 0,4892 CO, and 0,1263 H20. C = 65.62 ; H = 6-92. C,6H200, requires C = 65.75 ; H = 6.85 per cent. "i] r 4 m-Xylenomjfumaric Acid, (0 H ,)2C,H,-O*C( CO,H):CH* C0,H.-The ester is readily hydrolysed by boiling it with alcoholic potash. After thealkaline solution has been freed from alcohol by distillation on the water-bath, water is added t o the residue, and then an excess of dilute sulphuric acid. The solid, which is precipitated, dissolves in boiling water with diaculty, but with great ease in alcohol or ether,WITH ESTERS OF THE ACETYLENE SEHIES. PART VI.1189 and crystallises from dilute alcohol in yellowish prisms which melt and decompose at 2 1 0 O . On analysis : 0.2025 gave 0.4539 CO, and 0.0955 H,O. W = 61.13 ; H = 5.24. C,,H,,05 requires C = 61.01 ; H = 5.08 per cent. 6 8-Dimethyl-l ; 4-benxo~~rone-2-ccr,rbowylic Acid, ma-Xylenoxyfumaric acid dissolves in cold concentrated sulphuric acid, forming a red solution. After standing overnight, this is gradually poured into cold water, when a white, gelatinous precipitate is formed, which crystallises from dilute alcohol in colourless prisms. These melt and decompose at 27S0, and are freely soluble in alcohol but insoluble in water, On analysis : 0.2028 gave 0.4916 C02 and 0.0860 H,O. C = 61.11 ; H = 4 7 1 .C1,HloO4 requires C = 66.05 ; H = 4.59 per cent. CH3 0 \/' CO/CH 6 : 8-DimetlM~Z-1 : 4-benxopys.one) /\/ 'RH.--On heating the dimethylbenzopyronecarboxylic acid, it loses carbon dioxide, and a yellowish oil distils over which rapidly solidifies. The solid is freed from a small quantity of the acid which it contains by shaking the ethereal solution of the distillate with sodium carbonate. On evapora- tion of the ether, the dimethylpyrone remains behind ; it crystallises from dilute alcohol in colourless needles which melt a t 80-81" and dissolve in concentrated sulphuric acid, forming a colourless solution with a bluish fluorescence. On analysis : CH) 1 0.1974 gave 0,5482 CO, and 0.1047 H,O.C = 75.73 ; H = 5.89. Cl,H1,O, requires C = 75-80 ; H = 5.75 per cent. Action of Xoclium Phenolate on the Esters of P-Chlorocrotonic and p - Chloroisowotonic A cids. Ethyl P-Phenox ycrotonccte, CH3 C (0 C,H,) : CH CO,* C,H,. -Sodium phenolate reacts with ethyl P-chlorocrotonate as readily as with ethyl chlorofumarate on adding the ester (1 mol.) to a hot solution of sodium (1 at.) in an excess of phenol. The dark oily product, when sub- jected t o the same treatment as in the former cases, yields a colour- less oil with a pleasant aromatic odour, which distils at 147-148"1100 CONDENSATION OF PHENOLS WITH ESTERS. under 14 mm. pressure, and a t 21"/21" has the density 1.0726. analysis : On 0.1980 gave 0.5065 CO, and 0.1236 H,O. C12HI,0, requires C = 69.90 ; H The ester, on hydrolysis with alcoholic potash, is transformed into P-phenoxycrotonic acid, CH,*C(O*C,H,):CH*~O,H.On adding dilute sulphuric acid to the alkaline solution, after evaporation of the alcohol, the acid is precipitated as a white solid which dissolves in ether or alcohol with great ease, but only sparingly in water, and crystallises from dilute alcohol in colourless needles melting at 155". On analysis : C = 69-76 ; H = 6.93. 6.80 per cent. 0.2105 gave 0.4971 CO, and 0.1062 H20. C1,HloO3 requires C! = 67.41 ; I3 = 5.68 per cent. The silver salt is formed as a white precipitate, which is first gelx- tinous, but gradually becomes curdy, on adding silver nitrate to the solution of the acid in ammonia. The salt is insoluble in water, and has to be dried in a vacuum, since it turns brown when heated at ZOO".On analysis: C = 67-28 ; H = 5%5. 0.2805 left, on ignition, 0.1065 Ag. Ag= 37-96. CI,H,O,Ag requires Ag = 37.89 per cent, P-Phenoxycrotonic acid, as has bean mentioned (p. 1 l86), when dis- solved in concentrated sulphuric acid, or when boiled with dilute sul- phuric acid, suffers a decomposition similar to that of the aryl ethers ol /3-hy droxycinnamic acid, and furnishes carbon dioxide, phenol, and ace tone. P-Phenoxy~roz~~Zene, CH,* C( O*C,H,): CH, .--On heating P-phenoxy- crotonic acid in a vacuum, i t distils with partial decomposition ; this, however, is complete on distillation under the atmospheric pressure. The colourless oil so obtained, boils a t 170°, and has an odour resem- bling that of phenyl mustard oil. On analysis : 0.2400 gave 0.7118 GO, and 0.16 LO H,O. C,HloO requires C = 80.60 ; H = 7.46 per cent. As stated on p. 1186, ethyl /3-chloroisocrotonate yields the same pro- duct as ethyl 6-chlorocrotonate, when it is treated with sodium phenol- ate. The substance obtained from the former ester distils at 152" under 18 mm. pressure, as compared with 147-148' (under 14 mm. pressure) which we have found for the sample prepared from ethyl chloro- crotonate. Its composition, nioreover, has been verified by the fol- lowing analysis : C = 80.88 ; H = 7.45, 0.1938 gave 0.4960 CO, and 0.1178 H,O. C= 69.80 ; H = 6.75. C,,HI,O, requires C = 69.90 ; H = 6.80 per cent.THE IIY DROBROMIDES OF UNDECYLENIC ACID. 1191 The identity of both specimens of ethyl P-phenoxycrotonate is also supported by the fact that the acids formed from them on hydrolysis have the same crystalline forms and melting points, GONVILLE AND CAIUS COLLEGE, CAMBRIPGE.