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 OsO4 gave the cis-4,5- and 9,10-dihydrodiols. 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-bcd]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.