Biotransformation of 1-(4-chlorophenyl)-3,3-dimethyltriazene into 3-chloro-4-hydroxyaniline: intramolecular hydroxylation-induced chlorine migration during a catabolic degradation of a chemical carcinogen.

Five modified anilines were identified in ethyl acetate extract from hydrolysed urine of rats which had been injected with the carcinogenic 1-(4-chlorophenyl)-3,3-dimethyltriazene. 4-Chloro-2-hydroxyaniline (15.1%) and 4-chloroaniline (5.2%) were the most abundant metabolites arising by in vivo fission of the diazoamino group. The structures and distribution of 4-hydroxyaniline (less than 0.1%), 4-chloro-3-hydroxyaniline (0.7%) and of 3-chloro-4-hydroxyaniline (8.2%) suggest that these metabolites are derived from a common 3,4-epoxy intermediate and arise either by elimination of chlorine, by opening of the epoxide ring or by an intramolecular hydroxylation-induced chlorine migration, respectively.