Synthesis and Mutagenicity of Dihydrodiol Metabolites of Benzo[b] fluoranthene

The syntheses of the two major hepatic microsomal dihydrodiol metabolites of the environmental carcinogen, benzo[5]fluoranthene, are described. 1, 2-Dihydro-1, 2-dihydroxybenzo [5]fluoranthene was prepared from 11Hbenzo[b] fluorene-11-carboxylic acid. The key intermediate was l-oxo-1, 2, 3, 3a-tetrahydrobenzo[b]fluoranthene which was prepared by regiospecific cyclization of 1lR-benzo [b]fluorene-11-propionic acid chloride. 11, 12-Dihydro-11, 12-dihydroxybenzo[6]fluoranthene was synthesized from 2-methylfluoranthene via 12-oxo-9, 10, 11, 12-tetrahydrobenzo[b]fluoranthene. Both dihydrodiols were mutagenic toward Salmonella typhimurium 100, but their activities were less than that of benzo[b] fluoranthene.