Oxygenation of biphenyl by the reagent system Fe(MeCN)6(2+)-H2O2-Ac2O: an implication to the mechanism in mammalian metabolism.

2and 4-acetoxy derivatives, preferentially the 4compound,1a-el except for acetoxylation with Pd(OAc)2 which gives the 3-acetoxybipheny1.1f) Biphenyl is normally metabolized by hydroxylation to either the 2-, 4-, or both, hydroxylated derivatives. It was reported, however, that young rats hydroxylate biphenyl to both the 2and 4-hydroxy compounds whereas adult rats preferentially form the 4-hydroxy derivative:2a) Also, the in vivo hydroxylation of biphenyl is usually stimulated when animals are pretreated with inducing agents. For example, it has been reported that the formation of 2-hydroxybiphenyl is stimulated when rats and mice are pretreated with benzo(a)pyrene and that 4hydroxylation is stimulated when they are pretreated with phenobarbita1.2 b) In addition, a recent paper indicated that pretreatment with 3-methylcholanthrene caused simultaneous increases in both biphenyl 2and 4-hydroxylation in the in vivo assay system with rat liver microsomes.2c) It has also been reported that in vitro hydroxylation of biphenyl is genetically associated with the induction of aryl hydrocarbon hydroxylase (which may be cytochrome P-450) in responsive strains of mice.2d) Concerning these metabolic observations, we investigated oxygenation of biphenyl by the reagent system Fe(AN) 2+ 6 -H 2 0 2 -Ac 2 0;AN=MeCN,a