468 FATE OF BODY-FOREIGN SUBSTANCES 



Oxidation of Cyclic Nuclei. Taking up the question as to 

 the extent an oxidation or disruption of cyclic groups can 

 take place in the economy, 40 there is no doubt that these 

 cyclic compounds frequently effectively withstand even the 

 oxidation powers of the system, and at times may be either 

 excreted entirely unchanged (as is the case with phthalic 



/COOH 



acid, C^V^YVVTT* when introduced parenterally in rabbits) 41 



N 



or undergo merely hydroxylation. Thus, to take up a few 

 examples, benzol C 6 H 6 may pass into phenol C 6 H 5 (OH), 



aniline C 6 H 5 .NH 2 into paraamidophenol CoH 4 <^ , phenol 



/OH /\ 



C 6 H 5 (OH) into hydrochinon CH 4 <^ , indol r 1 - j into 



NH 

 /\ OH /\/\ 



indoxyl [ ~~| , naphthaline f I into naphthol, etc. 



\/\/ \S\S 



NH 



The views as to the movement of the hydroxyls observed in 

 this process of oxidation now and again observed, as in the 

 transition of tyrosin, 



into homogentisic acid, OH 



CH.NH 2 



COOH COOH 



have been stated in a previous lecture (Vol. I of this series, 

 pp. 51-52, Chemistry of the Tissues). 



40 Literature upon the Behavior of Benzol Derivatives in the Economy: 

 S. Frankel, Dynamische Biochemie, Wiesbaden, 1911, pp. 53-66. 



E. Przibram, Arch. f. exper. Pathol., 51, 372, 1904; J. Pohl, Biochem. 

 Zeitschr., 16, 68, 1909. 



