Spin trapping of the primary radical involved in the activation of the carcinogen N-hydroxy-2-acetylaminofluorene by cumene hydroperoxide-hematin.

We have verified that the cumene hydroperoxide-hematin system reacts with 5,5-dimethyl-1-pyrroline-1-oxide to form the nitroxide 5,5-dimethyl-pyrrolidone-(2)-oxyl-(1) (DMPOX). We have investigated the mechanism of this reaction and found that it is not a simple oxidation, as has been previously reported, but that DMPOX is formed via the spin trapping of a cumene hydroperoxyl radical followed by an intramolecular carbanion displacement. The activation of the carcinogen, N-hydroxyl-2-acetylaminofluorene, by the cumene hydroperoxide-hematin system is most likely mediated by cumene hydroperoxyl radical.