Studies in detoxication. 52. The apparent dissociation constants of some glucuronides, mercapturic acids and related compounds

This method has been applied to the deter- mination of catechols formed during the metabolism of fluoro-, chloro-, bromo-, iodo-and o-dichlorobenzene in the rabbit.Between 20 and 30 % of the monohalogenobenzenes metabolized are converted into the corresponding 4-halogenocatechols which are excreted mainly in conjugated forms for 2-3 days after dosing.Some 8 % of o-dichlorobenzene is dihydroxylated.The isomeric monochlorophenols aind phenol are also oxidized to catechols to a small extent (05-4 %).3. The halogenobenzenes also form small amounts (about 2-3 %) of p-halogenophenols and traces of the o-phenols.These were detected mainly by paper chromatography. The relation between mercapturic acid and o-dihydroxylation in these compounds is discussed, but no definite conclusions have been reached.5. It is shown that the formation of catechols from the halogenobenzenes need not be contrary to the free radical hypothesis of biological hydroxylation, although other explanations are also feasible.