— 158 — ; f[ 



Me nth one. Some time ago G. Vavon 1 ) described the reduction of 



v carvone by hydrogen in the presence of platinum. By reducing Z-menthone 



[«578 2 ) — 22,6°] by the same method, Vavon 3 ) has obtained a menthol with 



b. p. 208 to 209°; 98 to 99° (13 mm.); « 5 78 + 10,6°. The same menthol 



was obtainable from pulegone. Its rotation was low: «578 + 6,4°. 



H. Stobbe and A. Rosenburg 4 ) have ascertained that when menthone 

 is allowed to react with benzalacetophenone in the presence of sodium 

 ethylate, it yields a ketone alcohol, m. p. 128 to 129°: [«] D + 57,59°. It 

 was impossible to determine exactly the structure of this compound: it is 

 either a 2, 4-diphenyl-5-isopropyl-8-methyl-9-keto-4-hydroxybic?/cZononane or 

 a 2, 4-diphenyl-l-tsopropyl-6-methyl-9-keto-4-hydroxybici/c?ononane. The body 

 does not react with dimethyl sulphate, nor with acetic anhydride and 

 benzoylchloride or with phenyk'socyanate. This indifference towards all 

 the reagents in question on the part of a ketone alcohol is at first 

 somewhat surprising, but it agrees with the experience of Dieckmann and 

 von Fischer 5 ) that hydroxy compounds of exactly similar structure, namely, 

 the c^/cfohexanolone carboxylic esters, are equally incapable of being 

 benzoylated. 



So far it has been found impossible to unite other ring-ketones, such 

 as d-fenchone or camphor, with benzal acetophenone or other analogous 

 unsaturated ketones 6 ). 



In one of our earlier Reports we mentioned a paper by 0. Wallach 7 ) 

 on the decomposition of hydroaromatic ketones by heating with potassium 

 hydroxide. Wallach had already previously discovered 8 ) that heating 

 menthone oxime with potash gives rise to a decylic acid Ci H 2 o0 2 . 

 Recently the author 9 ) has again carried out the same experiments on a 

 larger scale and has obtained thymol as a by-product. The phenol was 

 identified from its phenylurethane (m. p. 103 to 104°), in addition to which 

 the urethane was split off by careful heating, in which process thymol 

 (m. p. 49 to 50°) was reconstituted. The acid reaction products consist 

 chiefly of decylic acid (b. p. about 250°), to which an isomeride is probably 

 admixed. It yields a methylester with b. p. 212 to 215°. The amide of 

 the acid melts at 108 to 109°. > 



*) Compt rend. 153 (1911), 68; Report October 1911, 150. 



2 ) It is not clear from the paper what was the source of the light used by Vavon. 



3 ) Compt. rend. 155 (1912), 286. 



4 ) Journ. f. prdkt. Chem. II. 86 (1912), 226. 

 B ) Berl. Berichte 44 (1911), 967, footnote. 



8 ) See R. Georgi and A. Schwyzer, Journ. f. prakt. Chem. II. 86 (1912), 237. 

 7 ) Liebigs Annalen 369 (1909), 98; Report April 1910, 181. 



. 8 ) Lieligs Annalen 296 (1897), 128. 



9 ) Ibidem 389 (1912), 194. 



