— 86 — 



condenses to zwphorone carboxylic ester 1 ) or (5-keto cyclogeraniolene 

 carboxylic acid ester, with the formula 



CH fl CH Q 



HX 



/\ 



CH.COOCH, 



OC x ^CCH 3 

 CH 

 a yellowish oil with a characteristic aromatic odour, b. p. 115 to 120 

 (4 mm.) or 136 to 140 (10 mm.). 



We can here only indicate briefly the further course of the syn- 

 thesis of /?-irone, (which is identical with the natural substance,) because 

 the authors propose to reserve full details of the subject for a sub- 

 sequent paper. It is based upon the preparation of zJ 4 -cyclogeranic 

 acid, which occurs in two stereo-isomerides : 



CH, CH 3 



HC 



HC 



CH-COOH, 



CH.CK 



CH 



This zJ 4 -cyclogeranic acid is obtained, together with A 3 - and zl 2 -cyclo- 

 geranic acid, in the course of the decomposition of d - chlorocyclo- 

 geranioladienecarboxylic acid 2 ) one of the products of reaction of 

 phosphorus pentachloride with z'^phorone carboxylic ester. Accord- 

 ing to a process of which details have already been given by Merling 3 ) 

 this acid is converted via the acid chloride, the acid anilide, the 

 phenylimide chloride, the diphenyl amidine and the diphenylmethyl- 

 enediamine into the corresponding aldehyde, zl 4 -cyclo-citral. This, 

 when condensed with acetone by the familiar process, yields /?-irone. 

 When wtfphorone carboxylic ester is reduced with sodium and 

 alcohol, the result is a mixture of two pairs of stereo-isomeric (5-di- 

 hydroxy-cyclogeranic acids, (<5-hydroxy-cyclogeraniolanecarboxylic acids) 

 Germ. Pat. No. 148207, CH CH 



C 



H C 



CH-COOH 



OH-HCv / CH.CH 3 

 CH 9 



*) Germ. Pat. No. 148080. See also Berl. Berichte 38 (1905), 979. 



2 ) Germ. Pat. No. 175 587. 



3 ) Berl. Berichte 41 (1908), 2064; Report November 1908, 183. 



