— 128 — 



CH, 



CH, 



-CH CH.CH a 



I 



C(CH 3 ) 2 

 I 

 -CH -CO 



CH 2 CH C(CH 8 ) a 



CH 2 

 I 

 C — 



CH 



-CO 



Fenchone formula 

 according to "Wallach 



CH 3 



Fenchone formula 

 according to Semmler 1 ). 



Nevertheless, the presence of a "bridge - bond" appears to be nec- 

 essary for bringing about the specific camphor-action; for carvone, in 

 which a double linking is present in the nucleus, shows already con- 

 siderable deviations from camphor in its physiological action; with the 

 rabbit, the toxic effect, characterised by uninterrupted convulsions, is 

 governed by an early occurring state of unconsciousness 2 ). The oxid- 

 ation-product obtained by Harries 3 ) from carvone on prolonged 

 shaking with barium hydrate in the presence of oxygen, by absorption 

 of one atom of oxygen, has an action not inferior to that of carvone; 

 in the organism, the oxidation of carvone probably takes place, in the 

 same manner as that of camphor, at a different place of the molecule. 

 The fact that the convulsion-producing action of carvone is connected 

 with the presence of the double linking in the nucleus, is clear from 

 the behaviour of menthone and pulegone. 



/CH,— CO /CH 3 /CH 2 -CO /CHg 



CH..CH NcH-CH CH 3 -CH \c:C 



\ X \ \ X \ 



CH — CH CH„ CH — CH CEL 



/CH-CH 2 /CH 2 

 CH Q -C NcH-C 



Menthone 



Pulegone 



X CH 2 -CH 2 

 Limonene 



CH 



If in carvone, instead of the two double linkings, the attachment 

 of two hydrogens each, and also another position of the CO- group 

 is assumed, we arrive at menthone, which has not by far the same 

 toxic action as carvone. Pulegone also, with a double linking in the 

 isopropyl side-chain, does not possess the convulsion-exciting action of 

 carvone, but has a chronic action on the parenchymatous organs, 

 which leads to a considerable fatty degeneracy 4 ). The slight toxicity 

 of the terpene limonene also proves that the presence of the carbonyl 

 group is necessary for producing the action of carvone. From pulegone 

 there is formed, by the action of sodium in alcoholic solution, pulegol, 

 with the alcohol -group CHOH instead of the ketone -group; it 

 consequently stands to pulegone, as borneol to camphor. But while 



*) Berl. Berichte 39 (1906), 2577, 3960. 



2 ) H. Hildebrandt, Zeitschr. f. physiol. Chemie 36 (1902) 



3 ) Berl. Berichte 34 (1901), 2105. 



4 ) W. Lindemann, Arch. f. exp. Pharmakol. 42 (1899). 



