In vitro studies on the microsomal N-oxidation of N-substituted benzamidines

Studies of the Microsomal N-Oxidation of N-Substituted Benzamidines in Vitro The metabolism of the N-mono- and N,N-disubstituted benzamidines 4 and 7 was studied employing 9000 g supernatant fractions of rabbit liver homogenates as enzyme sources. The potential metabolites, i. e. the amidoximes 5 and 8 and the N-hydroxyamidine 6b , were synthesized and used as reference products. Among the N-substituted derivatives only N-phenylbenzamidine (4a) is metabolized with detectable yields (t.l.c./m.s.) to the amidoxime 5a. Considering this finding and the metabolism of other nitrogen-containing functional groups, it is assumed that the cytochrome P-450 system preferentially oxidizes NH₂ groups.