Enzymic oxidation alpha to the acetylenic group in the metabolism of N-(5-pyrrolidinopent-3-ynyl)-succinimide (BL 14) in vitro.

1. The product of alpha-acetylenic oxidation of N-(5-pyrrolidinopent-3-ynyl)-succinimide (BL 14) by rat liver preparations was identified as N-(5-pyrrolidino-2-hydroxypent-3-ynyl)succinimide, by mass spectral analysis of metabolites of deuterium-labelled and non-labelled substrate. 2. The synthesis and physicochemical characteristics of the metabolite are reported. 3. Substantial amounts of the metabolite were obtained in preparations from phenobarbital-treated rats, while only minute amounts were formed by non-induced preparations. 4. Evidence for the involvement of an inducible cytochrome P-450 system in effecting this alpha-acetylenic oxidation is presented.