— 109 — 



the last formulae. The question, why also in pinocarvone the picean- 

 ring does not readily open, and no conversion of pinocarvone into 

 carvone takes place, is one that remains for the present unsolved 1 ) ; — 

 On the alcohol discovered by us in the oil of Eucalyptus Globulus Lab., 

 whose properties, according to Wallach, corresponded with those of 

 pinocarveol, we have already reported 2 ). 



When boiled with hydrochloric acid, nitrosopinene, according to 

 Kremers and v. Baeyer, yields carvacrol. By distillation of nitroso- 

 pinene with oxalic acid repeated more than 25 times, Wallach has 

 obtained in a small yield (3 to 4%) an intermediate product of this 

 decomposition, carvopinone, the ketone corresponding to nitrosopinene, 

 of the b. p. 94 to 96 (12 mm. pressure). But even when oxalic acid 

 is used, the ketone separated off undergoes a partial isomerisation 

 into carvone; mineral acids accelerate this process. The prisms of 

 the semicarbazone do not yet melt above 3 oo°, and are decomposed 

 only at a still higher temperature. Carvopinone, whose production in 

 the pure state is extremely difficult, cannot be regenerated in an ab- 

 solutely unchanged form from the semicarbazone, at it is partly 

 isomerised into carvone. By reducing crude carvopinone with sodium, 

 and oxidising the reduction-product obtained with chromic acid, pino- 

 camphone, C 10 H 16 O, was obtained, whose semicarbazone melts at 

 20 8°. Now the direct conversion of the nitrosopinene into carvone, 

 with oxalic acid or hydrochloric acid, also succeeded; in the latter 

 case it always contains a small quantity of carvacrol. 

 CH 9 CH Q 



HON = C- 



(CH 3 ) 2 C 

 I 

 CH 2 CH CH, 



nitrosopinene 

 CH, 



= C- 



-> 



(CH 3 ) 2 C 



CH 2 CH CH 2 



carvopinone 

 CH a 



= C- 



:CH 



OH 



I 

 (CH 3 ) 2 C 



CH 2 CH CH 2 



(intermediate product) 



= C- 



CH 



:CH 



CH 

 I 



CH 3 C = CH 2 

 carvone 



CH 2 



1 ) Comp. however also similar conditions under pinocamphone and pinic acid. 



2 ) Report October 1905, 33; comp. Gildemeister and Hoffmann, The 

 Volatile Oils, p. 528. 



