Synthesis of k-region derivatives of the carcinogen 1-nitropyrene

The synthesis of potential metabolites of 1-nitropyrene, resulting from oxidation at the K-regions, is described. Reaction of 1-nitropyrene with O_sO₄ gave the cis-4, 5- and 9, 10-di-hydrodiols. These were separated and oxidized with activated MnO₂ to give the corresponding 4, 5- and 9, 10-diones; further oxidation to the highly mutagenic lactones, 1- and 3-nitro-5H-phenanthro[4, 5-bed]pyran-5-one, was observed in these reactions. Reduction of the 4, 5-dione with KBH₄ gave the trans-4, 5-dihydrodiol, which was identical to one of the metabolites of 1-nitropyrene. Reduction of the 9, 10-dione gave an unstable trans-9, 10-dihydrodiol, which was characterized as its diacetate. The u.v. spectra, n.m.r. spectra and h.p.l.c. retention times of these compounds are presented.