Studies on the metabolism of Inabenfide (a new plant growth regulator) in rats. I. Characterization of metabolites in rats.

1. The metabolism of 4'-chloro-2'-(alpha-hydroxybenzyl) isonicotinanilide (Inabenfide, IBF) was studied in the rat. After intraperitoneal administration of IBF to rats, eight metabolites were detected in urine by g.l.c.-mass spectrometry and a stable isotope technique. 2. The major metabolites were hydroxylated IBF, and minor metabolites were dihydrodiol IBF, methylated catechol IBF, IBF ketone, IBF N-oxide and an amine derivative. 3. Of these metabolites, IBF ketone was produced by oxidation of the carbinol between the benzene rings, which is an interesting metabolite since similar oxidation between benzene rings is not well known. 4. Metabolism involving an NIH shift of chlorine and an epoxide-diol pathway for IBF are presented.