A series of monomethyl and dimethyl derivatives of benzo [b] fluoranthene (BbF) and benzo [k] fluoranthene (BkF) were synthesized in order to investigate the environmental occurrence and structural requirements for carcinogenicity of methylated nonalternant polycyclic aromatic hydrocarbons. 9-Methyl-BbF (5), 12-methyl-BbF (6), and 1-methyl-BbF (7) were prepared from the appropriate oxotetrahydro-BbF's (17-19). 8-Methyl-BbF (8) was ...