The metabolism of azo compounds

Abstract

When the urine from rats injected intraperi-toneally with azobenzene was diazotized and coupled with N-sulphatoethyl-m-toluidine, it gave an intense purple-red color, followed by separation of a purple precipitate. The precipitate was not produced from aniline or p-amino-phenol; moreover, the color dyed cotton for which aniline-type azo dyes have no affinity. Benzidine reacted with the coupling reagent to produce a substance identical with that formed from the urine. Apparently the urine contained aniline and a water-soluble derivative which, after acidification with dilute acid and subsequent addition of alkali, yielded benzidine. The water-soluble substance is probably the N-SO3Na or N-glucuronate derivative of hydrazoben-zene.