316 . iiEPORT— 1900. 



■which contains no asymmetric carbon atom ; the oxidation of the acid is 

 then readily understood : 



OH OH 



CMC = C CH,. CMC — C CH. COlIe COOH COOH 



III' 'II" I I 



CH,. j -> i CH, I -> CH,. + 



I I I II i I ' 



CJIe,— CH, COOH CMe,,-CH. COOH CJIe,— CH. COOH 



^-Campholeuic Acid. j8-Dihyilrox\ dihydio- •y-Acetyldimethj 1- Oxalic 



campliolenic Acid. butyric Acid. Acid.' 



5. TOKMATION AND CONSTITUTION OF CaMPHORPHORONE. 



When the calcium salt of camphoric acid is subjected to the action 

 of heat it is converted into calcium carbonate and camphorphorone, 

 CgHnO :— 



C,H,/ >Ca=C,H,4< )C0 + CaCOj. 



^CO.Q/ ■ ^/ 



Camphorone has the structure 



CHMe C : CMe^ 



CHo - CHa 



as it is converted into o-methylglutaric acid on oxidation, and may be 

 synthetically prepared by the action of sodium ethoxide on a mixture of 

 fi-methylketopentamethylene and acetone. Since these condensations in 

 saturated ketones occur only at a — CHg.CO — gi'oup, the action must be 

 expressed 



, CO. /^^\ 



CHMe CHo + 0CMe2 = CHMe C:CMe. + H„0 



■ I / " i I ' " 



CHo— CH., CH., — CHo 



as camiDhorphorone does not contain an acetyl group. - 



P.— THE FORMULA OF CAMPHOR. 



The earlier speculations regarding the constitutional formula of 

 camphor require no special discussion at the present time, as they are of 

 merely historical interest, and there is no doubt that the first great 

 advance was made by Bredt in his paper on 'The Con.stitution of 

 Camphoronic Acid,' •'' and the value of his deductions has been greatly 

 enhanced since the achievement of the synthesis of this acid by Perkin 

 and Thorpe,'' which provided a complete proof of the formula suggested for 

 it by Bredt. 



Starting from the formula of camphoronic acid, as it is generally 

 agreed we may do, and taking into account the fact that camphor readily 

 yields cymene by the action of various agents, Bredt was led to advance 

 the formula associated with his name. This formula has since been 

 assailed by several chemists, notably Noyes, Tiemann, Bouveault, Blanc, 



' See also Tiemann, £er., 28, 1079, 216G, &c. 

 » Bouveault, BnU. Soc. Chivi. [iii.], 23, 160, ^ Ber., 26, 3049. 



* Trans. Chem. Soc. 71, IIGH. 



