C8H  ,3~C /O~

C2H,4~C0 %0—war,/ — \L) . (r) (2) (3) (4) Thus camphor and its oxidation products are to be represented as CH2-CH- CIi2 (a) CH2' CH' CO_H CO2H COzIl ` C(CH3h (r) C(CH3)2 C(CH3)2 CH2'C(CH2)---CO(t), CH2'C(CH2)'CO2H, CHz' C(CHa)'CO2H Camphor, Camphoric acid, Camphoronic acid . Camphor yields three classes of halogen substitution derivatives known respectively as a, and x compounds, the positions being shown in the formula above . The a compounds result by direct substitution, the I4 and r derivatives being formed in an indirect manner . Cyancamphor, C,0Hi30•CN, is formed by passing cyanogen gas into sodium camphor, or by digesting sodium oxymethylene camphor with hydroxylamine hydrochloride (L . Claisen, Ann., 1894, 281, P . 351) . rr-Camphor sulphonic acid results from the action of fuming sulphuric acid on camphor (F . S . Kipping and W . J . Pope, Jour .

Chem .

Soc., 1893, 63, P . 573) . Camphoroxime, C,ol-116O:NOH, was first prepared by E . Nageli (Ber., 1883, 16, p . 497) . 1-Camphor is formed by the action of nitric acid on l-borneol (fit' . J . Pope and A . W . Harvey, Jour . Chem .

Soc., 1901, 79, p . 76)-r-Camphor melts at 178-179° C . (for its preparation see A . Debierne, Comptes rendus, 1899, 128, p . 1110; W . A . Noyes, Amer . Chem . Jour., 1905, 27, p . 430) . Camphoric acid . Four optically active and two inactive forms of this acid are known .

The most important is the d-

form, which is produced by the oxidation of d-camphor with nitric acid . It crystallizes in plates or prisms which melt at 187° C . Potassium permanganate oxidizes it to oxalic acid and Balbiano's acid, C5H1201, together with small quantities of camphanic, camphoronic and trimethyl succinic acids . It yields two series of acid esters, the allo-esters (I), formed by the partial saponification of the neutral esters, and the ortho-esters (2), formed by heating the anhydride with alcohols or sodium alcoholates . CH2' CH • CO211 CH2' CH' CO2R C1CH3)2 C(CH3)2 CH2' C(CH3)' CO2R CH2' C(CH3)' CO2H (r) (2) 1-Camphoric acid results on oxidizing l-borneol or matricaria camphor . It melts at 187° C. r-Camphoric acid is formed on mixing alcoholic solutions of equimolecular quantities of the B-and 1-acids, or by oxidizing i-camphor . It melts at 202-203° C . Camphoronic acid, C91-114O6 . From a study of its distillation products J . Bredt (Ber., 1893, 26, p . 3049) concluded that this acid (s) (2) Fenchone, C10H120, is trimethyl - (2 . 7 ) - bicyclo- (I • 2 .2). hepta- none-3 .

It occurs in d- and 1-forms, the former in oil of

fennel and the latter in oil of thuja . It may be obtained from these oils by treating the fraction boiling between 190-195° C. with nitric acid and distilling the product in a current of steam . The fenchones are pleasant-smelling oils which boil at 192-193° C., , and on solidification melt at 5-6° C . They do not combine with sodium bisulphite . They dissolve unchanged in cold concentrated hydrochloric and sulphuric acids, and are very stable; thus the monobromfenchone is only formed by heating the ketone with bromine to Too° C. under pressure (H .