ON THE CONSTITUTION OF CAMPHOR. 323 



whilst it is clear that the use of Bredt's formula would require the 

 assumption that isomeric change of a somewhat obscure character had 

 taken place. If this formula be the correct one, /3-campholenic acid, as 

 might be surmised from a consideration of its inactivity and its oxidation 

 products, is in reality homoisolauronolic acid. 



(c) The Formation and Troperties of Hydroxydihi/drolauronolic Acid. 



By the use of the Perkin-Bouveault formula the action of hypobromite 

 on rt-camphoramic acid would be represented 



CMe., . CMe . COOH CKe^ CMe.COOH 



CH., 



CH2— CH . CONH, CH2— CH . NH2 



and the formula so deduced for the amino-acid repi'esents a /3-amino acid, 

 which should naturally afford a /3-hydroxy acid on treatment with nitrous 

 acid. Since a /3-hydroxy acid would yield a /3-ketonic acid on oxidation, 

 the elimination of carbon dioxide and production of a ketone are easy to 

 understand (compare E. 2. c. i.). 



A consideration of the whole of the preceding facts leads to the con- 

 clusion that it is impossible to reconcile the results obtained in the various 

 departments of camphor chemistry without having recourse to the 

 assumption that, at certain points, intramolecular change takes place, 

 involving new arrangements of the carbon atoms. Thus, to take only one 

 example, the structure of the a- and /3-campholenic acids cannot be re- 

 presented by two formulae which differ only in the position of the double 

 binding as Tiemann suggested, for one acid clearly contains the grouping 



C C 

 : CMe . CMe^ Ch/ 



^C . 

 • and the other the complex 



: C . CMe., . CH, . C . C. 



The formation of isocamphoronic acid on the one hand and of iso- 

 lauronolic acid on the other is also incapable of explanation on any other 

 grounds than that of intramolecular change ; and it would appear advis- 

 able, therefore, to consider the whole of the evidence from a broad stand- 

 point, and, having decided which is the more probable view, to endeavour 

 to ascertain the points at which difficulties first arise, and only then to 

 seek for explanations. It is obvious that it would be altogether ill-advised 

 to adopt the usual course and to take any one derivative, however well 

 established its structure may be, and however simple its apparent mode 

 of derivation, and to use this as the basis on which to form our conclu- 

 sions, employing a forced explanation for each inconvenient fact in turn. 



Looking at the question, first, from a general point of view, without 

 regard to ultimate structure, it must be obvious that the probabilities are 

 greatly in favour of the view that the ketone ring in camphor is a penta- 

 methylene nucleus, as witness the readiness with which the substance is 

 obtained from homocamphoric acid. Moreover the properties of homo- 

 camphoric acid itself approach more neai-ly those of an adipic than glutaric 

 acid, since under no circumstances does it appear to yield an anhvHride. 



Y 2 



