DERIVATIVES OR PHENYLDIHYDRORESORCIN. 1383 CL.- Derivatives of Yheny ldihy droresorcin . By ALEXANDER JOHN BOYD PERCY HERBERT CLIFFORD and MAURICE ERNEST PROBERT. THE following is a brief account of some experiments commenced by one of us (A. J. B.) in 1914 a t the suggestion of Professor A. W. Crossley the work was interrupted and could not be resumed until October 1919 and although we (P. H. C. and M. E. P.) cannot now coniplete the original plan it is thought advisable briefly to place on record such results as have been obtained. The original object of the work was twofold; first more fully t o examine certain derivatives of phenyldihydroresorcin because some of them notably phenylcyclohexanol had been encountered in the course of other experimental work then in progress (com-pare Crossley and Renouf T.1915 109 GOB) and secondly to investigate the influence and behaviour of aromatic groups such as phenyl in hydroaromatic hydrocarbons. Phenyldihydroresorcin was therefore converted into phenylcyclohexane by a series of reactions which had been successfully employed in previous case 1384 BOYD CLIFFORD AND PROBERT : (Crossley and Renouf T. 1905 87 1488). The dihydroresorcin (I) when treated with phosphorus trichloride readily yields chlorophenylcyclohexenone (11) which on reduction with sodium in moist ethereal solution gives phenylcyclohexanol (111). CHPh CHPh CHPh H,C/\CH - H,C/\CH -+ Cld Ico \/ H0-d ICO CH CH, \/ CH (1.) (11.) (111.) UHPh CHPh Hydrogen bromide converts the alcohol into bronLophenylcyclo-hexane (IV) in which substance the bromine is readily displaced by hydrogen under the influence of zinc dust in aqueous-alcoholic solution giving rise t o phenylcyclohexane.The hydrocarbon is easily obtained in about 74 per cent. of the theoretical amouiit, and has all the properties previously ascribed to it by other workers. Certain other derivatives of phenyldihydroresorcin were of necessity isolated in the course of the work and they are described in the experiirental part of this communication. EXPERIMENTAL. Phenyldihydroresorcin was prepared from ethyl malonate and styryl methyl ketone (benzylideneacetone) using the conditions described by Crossley and Renouf (T. 1915 107 608). The latter was obtained from benzaldehyde and acetone as described by Claisen and Ponder (Annalen 18'84 223 139) but it was found that two vacuum distillations did not remove entirely the unchanged benzaldehyde and the following procedure was there-fore adopted to purify the ketone.The crude product was dis-tilled once in a vacuum and the distillate which crystallised on cooling was broken up spread on a porous plate and exposed to the air for two days. This caused oxidatmion of the benzaldehyde to benzoic acid which was removed by washing with dilute sodium hydroxide solution. After further washing with water the ketone was dried and crystallised from light petroleum (b. p. 60-8OO) DERIVATIVES OF PHENYLDIHYDRORESORCIN. 1385 Action of Bromine on P~enyldihydroresorcin.-~ive grams of phenyldihydroresorcin (1 mol.) were suspended in 50 C.C.of dry chloroform and a solution of 4.3 grams (2 atoms) of bromine in dry chloroform was gradually added with constant shaking when the resorcin gradually dissolved. On further addition of bromine, much hydrogen bromide was evolved and a bulky white solid separated which was collected washed with chloroform dried on a porous plate and crystallised from aqueous alcohol (Found: Br = 29-95 CI2H1,O2Br requires Br = 29-96 per cent.). 4-Bromophenyldi?tydroresorcin CHPh<C,:.-,O>CHBr CH *co crystal-lises from aqueous alcohol in compact clusters of short glistening needles melting a t 177O with rapid evolution of gas. (If heated sufficiently rapidly the melting point may be found as high as 1 8 9 O . ) It is soluble in alcohol acetone or ethyl acetate sparingly so in chloroform or benzene on boiling but insoluble in ether or light petroleum.Oxidation of PltenyEdihydroresorcin .-Five grams of the resorcin were suspended in 125 C.C. of water and treated with a 4 per cent. solution of potassium permanganate until the latter was no longer decolorised the whole being continuously mechanically shaken. About five hours were required for the completion of the oxida-tion. The product worked up in the usual way gave 3.8 grams of a solid fro& which were isolated by repeated recrystallisation from dilute hydrochloric acid two acids A and B . The acid A melted a t 139O nor was this melting point lowered on admixture with a specimen of pure P-phenylglutaric acid prepared for purposes of comparison (see p.1387). The acid B melted a t 166.5-167° and its melting point was not lowered when mixed with phenylsuccinic acid (see p. 1386 for the proof of the identity of this acid). Owing to the great similarity in solubility of 15-phenylglutaric acid and phenylsuccinic acid it was not found possible to separate the whole of ,4 and B but there was no evidence of the presence of another compound in the remaining mixture. Action of Phosphorus Trichloride on Phenyldikydrores0rcin.-Sixty grams (3 mols.) of phenyldihydroresorcin were heated with 22 grams (1.5 mols.) of phosphorus trichloride and 240 grams of dry chloroform on a water-bath for three hours. After distilling off the chloroform the residue was poured into cold water and extracted four times with ether the ethereal solution thoroughly washed with sodium hydroxide solution (4 per cent.) then with water dried over calcium chloride and the ether evaporated.The oily residue which readily solidified on cooling was crystallised V O t . CXVLT. 3 1386 BOYD CLIFJ?ORD AND PROBERT : twice froiii light petroleum (b. p. 60-80O) (Found C1= 17.00. CI2H,,OC1 requires C1= 17.19 per cent.). 5 -Chloro-1-phe nyl-A4-cycloh c~cn-3-on e CHPh<CH CH IeCC1>CH -GO , L the yield of which is about 65 per cent. of the theoretical crystal-lises in colourless transparent plates melting a t 63.5-64O. It possesses a rather pungent odour is somewhat sternutatory and has an irritating effect on the skin. It is soluble in alcohol ether, chloroform acetone benzene or ethyl acetate and in light petroleum on boiling.When boiled with absolute alcohol and the solution allowed to remain in a moist atmosphere for several days, the ketone reverts to phenyldihydroresorcin. There is evidence that the ethyl ether of phenyldihydroresorcin (Vorlander and Erig, Annalen 1897 294 304) is an intermediate product but the change has not been fully investigated. The oxime crystallises from alcohol in almost colourless short needles melting and decomposing a t 1570 (Found N = 6 . 5 . C,2H,20NC1 requires N = 6.32 per cent.). The semicarbasone prepared in the usual manner crystallises from alcohol in rosettes of small colourless needles. When heated in a capillary tube it softens a t 150-5* melts a t 153*5O and decomposes a t 191O. It is insoluble in the usual organic solvents, with the exception of ether benzene and light petroleum in which it is only very sparingly soluble even on boiling (Found: N =.15.91.C13H,,0N3C1 requires N = 15.94 per cent.). Oxidation of Chlorophenylcyclohexenone .-Twenty grams of the chloro-ketone were suspended in 500 C.C. of water and treated with a 4 per cent. solution of potassium permanganate until the latter was no longer decolorised the whole being continuously shaken mechanically. Oxidation took place slowly requiring twenty hours for completion. The product worked up in the usual way, gave 13.5 grams of solid from which were isolated by repeated recry stallisation from dilute hydrochloric acid solution A an acid melting a t 167O; B an acid melting a t 138*5-139*5°; and C a small quantity of an acid melting a t 121-121.5° which was obtained by extraction of the above mixture with cold benzene and recrystallisation of the residue obtained on evaporation of the solvent.The acid ( A ) yielded an anhydride melting at 53-54O and an anilic acid melting a t 169-170° when treated according to the directions given by Hann and Lapworth (T. 1904 85 1366) for the preparation of these derivatives of phenylsuccinic acid. The fact that these data coincide with those given by Hann and Lapworth proves the acid ( A ) t o be phenylsuccinic acid DERIVATIVES OF PHENYLDIHYDRORESORCIN. 1387 The melting point of the acid B was not lowered on admixture with pure P-phenylglutaric acid (m. p. 138-140O) prepared for t'he purposes of comparison ( B e y .1899 32 1879). On treating its silver salt with methyl iodide in dry ethereal solution an ester resulted melting a t 83*5-84*5OY nor was this melting point lowered on admixture with a specimen of the pure dimethyl ester of P-phenylglutaric acid (m. p. 84-85O) prepared for the purposes of comparison (Ber. 1898 31 1828). Only a very small quantity of the acid C was obtained after recrystallisation froin water. On admixture with pure benzoic acid the melting point was not lowered appreciably and although the amount of the acid was too small to admit of further purifi-cation or preparation of derivatives its odour and behaviour towards various solvents support the supposition that it is benzoic acid. Reduction of Clzloroyl~enylcycloiLezenone.-Q~zantities of 20 grams of the chloro-ketone were treated with twice the calculated quantity of sodium in moist ethereal solution as described by Crossley and Renouf (T.1905 87 1494). When all the sodium had dissolved the ethereal solution was separated washed with water until no longer alkaline dried over anhydrous potassium carbonate and the ether evaporated. The residue was submitted to steam distillation until a test portion of the distillate gave no turbidity on adding potassium carbonate. The distillate contained a solid in suspension crystallising in colourless needles which were collected and crystallised from light petroleum (b. p. 80-looo) (Found C=81*60; H=9*36. C,,H,,O requires C=81*76; H=9.16 per cent.). 1-Phenylcyclohexan-3-01 C H P ~ < ~ ~ ~ ~ * C H ( ~ ~ ~ > C H ~ was pre-pared although not fully described by Crossley and Renouf (T., 1915 107 608) for comparison with a by-product obtained in the reduction of phenyldihydroresorcin.It is obtained in 50-53 per cent. of the theoretical amount and crystallises in fine colourless needles melting a t 79.5-80.5° and possessing a pleasant odour soniewhat resembling that of geranium. It is soluble in the usual organic solvents but only sparingly so in cold light petroleum. When dissolved in absolute alcohol and the solution gradually treated with concentrated sulphuric acid it gives a greenish-yellow colour slowly changing to brown with a green fluorescence. The ace t y l derivative prepared in the usual manner crystallises from a small quantity of alcohol in stout transparent oblong plates melting a t 43-44O and is readily soluble in all the usual organic solvents.It can be distilled in air without decomposition 3 3 1385 BOYD CLIFFORD AND PBOBERT and boils a t 300° (Found C = 77.05 ; H = 8-69. CT,,H,,O requires C = 77.01 ; H = 8-32 per cent.). The benzoyl derivative is readily obtained in quantitative yield. It crystallises from ethyl or methyl alcohol in rosettes of colourless prisms melting a t 6S0 and is readily soluble in all tho usual organic solvents on boiling (Found C = 81-28; H = 7-36. C,,EImO2 requires C = 81.39 ; H = 7.19 per cent.). The o-nitrobenzoyl derivative was prepared by allowing mole-cular proportions of o-nitrobenzoyl chloride and the alcohol t o react in pyridine solution. It crystallises from dilute solution in ethyl or methyl alcohol in rosettes of minute needles melting a t 70* (Found N=4*49.Action of Bydrogen Bromide on .Pl~enylc~clohexan-3-ol.-Quantities of 5 grams of the alcohol were sealed up in small soda-water bottles with 25 C.C. of fuming hydrobromic acid saturated a t Oo and heated in a water-bath for one hour. The resulting liquid which was in two layers was poured into excess of cold water and the lower oily portion dissolved in ether. The ethereal solution was washed with water then with dilute sodium carbonate solution finally again with water dried and the ether removed, the residue being distilled under diminished pressure (Found : Br = 33.49. C,,H,,Br requires Br = 33-42 per cent.). 3-Bromo-l-phenyZcycloliezane the yield of which is almost quantitative is a clear colourless liquid boiling a t 186-187O/ 40 mm.with a pleasant odour resembling that of geraniol yet somewhat reminiscent of the odour of oranges. A c t ion of 2 inc D zis t on 3-Bromo-1 -p henylcycloh e xnne .-Twenty-four grams of bromophenylcyclohexane were mixed with 75 C.C. of 90 per cent. alcohol and sufficient absolute alcohol to form a clear solution to which were added 38.5 grams of zinc dust mixed with an equal volume of sand and the whole was heated on the water-bath for ten hours. The resulting liquid was poured into a large excess of water the mixture extracted with ether the ethereal solution washed with water dried and the ether evaporated using a fractionating column. The resulting oil, which was nearly colourless was heated over metallic sodium for two hours and then distilled when 13 grams passed over a t 232-233" and after one further distillation from sodium 11-9 grams (yield 74 per cent.of the theoretical) were obtained boiling constantly a t 233-234O/ 755 mm. It readily solidified when cooled to just below Oo and melted at 6.5O. These properties agree closely with previous descriptions of the properties of phenylcyclo-hexane (Willstaitter and Lessing Rer. 1901 34 506 ; Eijkman, Cl9HI9O,N requires N=4.31 per cent.) DERIVATIVES OF PHENYLDIHYDRORESORCIN. 1389 Chem. Weelcblad 1903 1 7 ; Rleerwein and Kremers Anmale,n, 1919 419 121). In order further to establish its identity with phenylcyclo-hexane 6 grams of the substance were treated with fuming nitric acid (D 1.50) until the addition of acid caused no further visible change (about 10 C.C.of acid were used).‘ The mixture was poured into water and the heavy oily layer dissolved in ether and worked up in the usual manner. On evaporation of the ether 7.9 grams of a yellow oil were obtained which on cooling gave a crystalline deposit weighing 3.8 grams after drying on a porous plate. I t crystallised from aqueous alcohol in large colourless lustrom leaflets melting a t 57-5-580 (Kursanov Annalen 1901 318, 309 gives the meltipg point of p-nitrophenylcyclohexane as 5 7-5-5 ~ - 5 0 ) . Preparation of Ph enylcyclo hexan- 3 -one CH Ph< CH,*CH2 CB~-CO>CH,. -Fourteen grams of phenylcyclohexan-3-01 were added to 126 grams of Beckmann’s chromic acid mixture [60 grams (1 mol.) of potassium dichromate and 50 grams (2.5 mols.) of sulphuric acid in 300 C.C.of water] the whole being well shaken. The tempera-ture rose to 45O when a reaction set in which was soon complete. The mixture was then kept a t 50-55O for thirty minutes with constant shaking extracted with ether the ethereal solution worked up in the usual way and dried. After evaporating the ether the residual colourless oil was distilled under diminished pressure when 12.7 grams passed over a t 1.69-169*5°/18 mm. (Found C = 82-52 ; H = 8.42. C,,H,,O requires C = 82.72 ; H=8*10 per cent.). l-Phenylcyclohe~an-3-one the yield of which is practically quantitative is a colourless liquid boiling a t 169-169.5O118 mm. and 28?-288O/736 mm. which does not solidify when cooled to - loo.With alcoholic sulphuric acid it gives a reddish-yellow solution with a green fluorescence. The semicar bazone prepared in the usual manner crystallises from alcohol in radiating clusters of glistening prisms melting a t 167O. It is soluble in methyl or ethyl alcohol chloroform or ethyl acetate and in acetone benzene or light petroleum on boiling, but only very sparingly so in ether (Found N=18*22. C,,HI70N3 requires N = 18.18 per cent.). The oxime crystallises from alcohol in colourless ill-defined plates which melt a t 128-129O but begin to shrink a t about 12O0. It is insoluble in light petroleum and only sparingly soluble in ether but dissolves readily in the other usual organi solvents especially on warming (Found N = 7.34. C,,H,,ON requires N = 7-41 per cent.). The authors desire to express their sincere thanks to Professor Crossley for originally suggesting the work and for the help given by him during it,s progres‘s. ORGANIC RESEARCH LABORATORY, KING’S COLLEOE STRAND W.C. 2. [Eeccived October 6thy 1920.