The oxidation of alkyl sulfides, sulfoxides, and sulfones was examined with either rabbit liver microsomes or a reconstituted system containing purified cytochrome P-450, S-dealkylation being found to take place more readily with alkyl sulfides bearing a higher acidic α- hydrogen. Similar results were obtained in the oxidation of alkyl sulfides by hydroxyl radical. Both S-dealkylation and S-oxygenation products are presumed to be formed via the cation ...