— 152 — 



course of the work referred to above and also some other dicarboxylic 

 esters whose two carboxethyl groups are in some cases linked to the 

 same carbon atom, and sometimes to different carbon atoms in different 

 distances from each other. When heated with alcohol, the esters were 

 partly split up into aliphatic tricarboxylic esters. 



In connection with the above work, Kotz and Mich els report 

 on the differences in the easiness with which semicarbazones are formed 

 in the case of cyclohexanones. 



Carvone. As already described in our last Report, A. Lapworth 1 ) 

 obtained by hydrolysis of cyanodihydrocarvone, two stereo isomeric 

 acids. The neutralised /?-acid yields with prussic acid a cyanohydrin. 

 This now, like the cyanodihydrocarvone cyanohydrin formed from H C N 

 and cyanodihydrocarvone, can, according to Lapworth 's 2 ) further studies, 

 be readily hydrolysed by mineral acids, and finally be converted in 

 2-methyl~5-isopropenyl-zl 2 -tetrahydroisophthalic acid, which on reduction 

 yields a mixture of isomeric 2-methyl-5-isopropenyl-hexahydrophthalic 

 acids. Although these latter are unsaturated, they cannot be further 

 reduced by sodium amalgam. The addition products of cyanodihydro- 

 carvone with hydrohalogen acids are well-characterised crystalline bodies. 

 The hydroiodide can be reduced with zinc and methyl alcohol to a 

 mixture of cyanodihydrocarvone and cyanocarvomenthone, of which 

 the last-named is converted by the action of acids in carvomenthone- 

 carboxylic acid, and by alkalis in carvotanacetone. 



Pulegone. A. Lapworth 3 ) has conjointly with W. L. Clarke, 

 studied the action of potassium cyanide on pulegone. The body 

 C u H 17 ON formed in this reaction, can according to Hann and 

 Lapworth 4 ) by readily converted in menthonecarboxylic acid (m. p. 

 1 20 to 121 ). When treated with acetyl chloride, or heated with 

 mineral acids, this yields an unsaturated lactone C u H 16 2 , from which 

 by shaking with ammonia the original body C n H 17 ON, can be 

 regenerated. This body had long been wrongly regarded as cyano- 

 menthone; in reality it represents an anhydramide of the following 

 constitution: — 



/CH 2 — CH 2 v 

 CH a .CH( >CC(CH,) f v 



X CH 2 C^ >CO 



x ) Proceed, chem. Soc. 22 (1906), 164; Report October 1906, 132. 



2 ) Proceed, chem. Soc. 22 (1906), 285; Journ. chem. Soc. 89 (1906), 1819. 



3 ) Proceed, chem. Soc. 22 (1906), 285; Journ. chem. Soc. 89 (1906), 1869. 



4 ) Proceed, chem. Soc. 20 (1904), 54. 



