OXIDATION OF CYCLIC NUCLEI 



469 



In many cases, again, oxidation takes place in the nuclear 

 ring, with change of - OH = groups into - CO -. Thus, ac- 



cording to Fiihner, 42 quinolin 



passes into quinolin- 



qumon, 

 CO 



CO 



acridin 



into oxyacridon 



As an example of a dehydration of hydro aromatic com- 

 pounds in the body may be mentioned the long known transi- 

 tion of quinic acid (tetraoxycyclohexancarboxylic acid) into 

 benzoic acid, and the change of hexahydrobenzoic acid, as 

 observed by E. Friedmann, 43 into benzoic acid, 



CH 2 



CH. 



Nor is there any dearth of examples of nuclear disruption in 

 the body. Here may be classed the excellent observation of 

 Jaffe 44 upon the occurrence of muconic acid in the urine 

 after administration by mouth of benzol, 



BENZOL 

 CH 



MUCONIC ACID 



CH 



HC 

 HC 



CH 

 CH 



HC 

 HC 



COOH 

 COOH 



CH 



CH. 



43 H. Ftihner, Arch. f. exper. Pathol., 51, 391, 1904; 55, 27, 1906. 



43 E. Friedmann, Biochem. Zeitschr., 85, 49, 1911. 



44 M. Jaffe, Zeitschr. f. physiol. Chem., 62, 57, 1909. 



