Synthesis of Potential Phenolic Metabolites of Benzo[b]fluoranthene

The syntheses of the 12 isomeric hydroxybenzo[b]fluoranthenes (hydroxy-BbF, 1–12) are described. 1-Hydroxy-BbF was prepared by treatment of 1-oxo-1,2,3,3a-tetrahydro-BbF (13) with Pd/C. 2-Hydroxy-BbF was synthesized by reduction of 13 with NaBH₄, followed by dehydration, epoxidation, and treatment with Pd/C. 3-Hydroxy-BbF was obtained by reduction of 13 with Zn(Hg) followed by oxidation with Triton-B, dehydration, epoxidation, and aromatization. 4-Hydroxy-BbF and 7-hydroxy-BbF were prepared by reaction of ace-phenanthrylene with 1-acetoxybutadiene, aromatization, hydrolysis, and separation by HPLC. 5-Hydroxy-BbF was synthesized by reaction of o-bromobenzaldehyde with 3-methoxyfluorene, followed by cyclization with KOH and quinoline, hydrolysis, and purification by HPLC. 6-Hydroxy-BbF was obtained by regiospecific cyclization of 3-methoxy-11H-benzo[b]fluorene-11-propionic acid (33), followed by reduction, dehydration, aromatization, and hydrolysis. 8-Hydroxy-BbF was synthesized by dehydration of 7b,8-dihydro-7b,8-dihydroxy-BbF (39). 9-Hydroxy-BbF and 12-hydroxy-BbF were prepared by treatment of the corresponding oxotetrahydro-BbFs with Pd/C. 10-Hydroxy-BbF and 11-hydroxy-BbF were synthesized by reaction of fluorene with the appropriate bromomethoxybenzaldehyde followed by cyclization with hydrolysis.