ON THE CONSTITUTION OF CAMPHOR. 325 



of the latter is in strict accordance with the requirements of Bredt's 

 formula. 



It is certainly difficult to understand the behaviour of hydroxydihy- 

 drolauronolic acid, but until more is known of this acid it is possible to 

 attach undue significance to the point. 



It is impossible to overlook the fact that the Bredt formula affords an 

 excellent explanation of the behaviour of a very large number of camphor 

 derivatives, and is, in fact, the only formula which will do so, and that the 

 same words apply to the Perkin-Bouveault formula when the remainder, 

 namely, isolauronolic acid and /3-campholenic acid, are referred to. 



Since the constitutions of the two different series of compounds appear 

 to have been established with such a high degree of probability, one is led 

 to the belief that there may, after all, be some close connection between 

 the two series which has escaped observation owing to the occurrence of 

 unsuspected isomeric change — a phenomenon which it is generally admitted 

 must be the cause of the present divergence of opinion on the matter. 



It does not require much consideration to observe that if this explana- 

 tion be correct the isomeric change must occur during the formation of 

 isolauronolic acid, and in the transformation of the a- to the /3-cam- 

 pholenic derivatives, so that a comparison of the probable formulae of 

 these substances before and after the change should allow us to gather if 

 there is any simple connection between them. 



^^CH.COOH ^^C.COOH 



CHo I CHo II 



I " CMea I "CMe 



01x2 I OHo I 



"^--C.COOH \C 



Me Mca 



Camphoric Acid. Isolauronolic Acid. 



CH ^^^\ 



CHg II CH., 

 CMe., I I CMe j 



CH I COOH CH, I COOH 



"-=..0 C 



Me Mej 



a-Campholenic Acid. j8-Campholenic Acid. 



It is fairly clear that the apparent change consists in the migration of 

 a' methyl group to an adjacent carbon atom in both cases. The alteration 

 of the position of the double binding in the campholenic derivatives is of 

 little consequence, as the change is probably preceded by the formatioix 

 of a lactone in some cases, of an imide in others, and these derivatives 

 contain no double binding. Possibly the change in the former case may 

 be represented 



