6 4 



SCIENCE PROGRESS 



camphor is converted to carvacrol (II.), which is also of known 

 structure — 



CH3 — CH — CH3 



I 



CioHi 6 — H-. 



Camphor. 



OH 



CH 3 



(II.) Carvacrol. 



All the above reactions are satisfied by the camphor formula 

 (III.) proposed by Kekule in 1873. It does not, however, account 

 for the saturated character (lack of additive power) in camphor, 

 nor for its oxidation, which is of great importance for the 

 determination of its constitutional formula. 



Formula IV. was put forward by Kannonikow in 1883, and 

 V. by Bredt in 1884. 



CH3-CH-CH3 CH 8 -CH-CH 3 



I I 



CH C 



CH. 



CH 



CH 2 CH.) 



CO CH 



CO CH, 



CH 2 CH 



CH 3 



(in.) 



Kekule. 



CH 3 



(IV.) 

 Kannonikow. 



That Bredt was correct and Kannonikow incorrect in the 

 position of the carbonyl (CO) group is shown by the conversion 

 of camphor to carvacrol considered above. Finally, Bredt 

 modified his formula in 1893 to the form shown in VI. 



The oxidation of camphor to camphoric acid (VII.) and 

 camphoronic acid (VIII.) is then formulated as follows : 



CH, OH CH 2 



I 

 CH3-C-CH3 



I 

 CH 2 C CO 



I 

 CH 3 



(VI.) Camphor. 



CH 2 



-CH- 



I 



-COOH 



CH 3 -C~CH 3 



CH, C COOH 



I 

 CH 3 



(VII.) Camphoric acid. 



COOH 



COOH 



I 

 CH3— C— CH3 



I 



CH 2 C COOH 



I 

 CH 3 



(VIII.) Camphoronic acid. 



