N-Hydroxylation: A new metabolic reaction observed in the rat with the carcinogen 2-acetylaminofluorene.

In their comprehensive work on 2acetylaminofluorenel (Fig. 1) the Weisburgers and Morris (l-4) have identified six phenolic metabolites of this carcinogen in the urine of adult rats. During recent studies (5) on this compound we have encountered a new acidic urinary metabolite. This metabolite is of interest since its excretion is greatly reduced by administration of a-methylcholanthrene, a potent inhibitor (6,7) of the carcinogenic activity of 2-acetylaminofluorene, whereas the excretion of certain of the phenolic metabolites is increased (5). The new metabolite has now been identified as N-hydroxy-2-acetylaminofluorene2 (Fig. 1). Its isolation, characterization, and synthesis form the subject of this report.