— 125 — 



to the same carbon-atom, there may originate, with loss of hydro- 

 chloric acid, on the one Hand a fenchene of the formula I, "camphor 

 fenchene", but on the other hand there might be formed with ring- 

 disruption between the carbon atoms I and 6, a fenchene of the 

 formula II, "isofenchone fenchene": — 



H 2 C 



CH 



4 3 



CH, — C 



CH 9 



CH, 



H„C 



CH 



1 



-> 



CC1 — CH, 



H C 



H C 



CH, 



C = C H., 



CH 



CH, — C — CH Q 



Fenchyl chloride 

 and H 2 C 



HC^- 



^^CH 2 

 II. Isofenchone fenchene 

 Formula II is identical with 



(CH 3 ) 2 = C CH- 



CH 2 

 I 

 — CH 



I. Camphor fenchene 

 CH, 



CH, 



CH, 



H 9 C 



C = CH, 



It this is accepted, the formation of the two semi-cyclic fenchenes 

 from Wallach's fenchone formula could be explained. But according 

 to more recent investigations by Semmler, this hypothesis cannot be 

 sustained without further proof. Particularly by the results of the 

 oxidation in alkaline and neutral solutions, which led from fenchone 

 to isocamphoronic acid and dimethyl tricarbally lie acid, Semmler was 

 induced to draw up the following formula for fenchone: — 



H,C 



H 9 C 



CH 

 I 

 CH 2 



I 

 C — 



(CH 3 ) 2 



CO 



CH, 



The formation of the two acids could be explained from this 

 formula without re-arrangement. Gardner and Cockburn 1 ) also ob- 



*) Journ. Chem. Soc. 73 (1898), 708. 



