Studies in detoxication. 51. The determination of catechols in urine, and the formation of catechols in rabbits receiving halogenobenzenes and other compounds; dihydroxylation in vivo.

Naphthalene, anthracene and phenanthrene are metabolized in rats and rabbits to 1:2-dihydroxy compounds which have been proved to be 1:2dihydro-1:2-diols (Young, 1950; Boyland, 1950). In the benzene series, an o-dihydroxy compound, 4-chlorocatechol, is a major metabolite of chlorobenzene in the rabbit (Spencer & Williams, 1950; Smith, Spencer & Williams, 1950). Many monosubstituted benzenes, e.g. phenol and nitrobenzene (cf. Robinson, Smith & Williams, 1951; Garton & Williams, 1949) also form small amounts of catechols. The addition or substitution of two hydroxyl groups ortho to each other, i.e. o-dihydroxylation, appears therefore to be a biological reaction of several aromatic compounds, and may result in the formation of reduced diols of the type mentioned above (this reaction has been called 'perhydroxylation') or of catechol derivatives, in which the aromatic ring is not reduced. Whether these two forms ofdihydroxylation are related is not known at present. The objects of the present work were to develop a quantitative method for the determination of catechols in the urine of rabbits receiving benzene derivatives and to find out whether other halogenated benzenes behaved like chlorobenzene.