Synthesis of the Major Metabolic Dihydrodiols of Benzofluoranthene

Article abstract of DOI:10.1021/jo00381a025

Syntheses are described for the major dihydrodiol metabolites of benzofluoranthene. trans-4,5-Dihydro-4,5-dihydroxybenzofluoranthene was prepared via 9-methoxy-11H-benzofluorene.Two of the intermediates in this synthetic sequence, 4-hydroxybenzofluoranthene and benzofluoranthene-4,5-dione, are also suspect metabolites of the parent hydrocarbon.An improved synthesis for trans-9,10-dihydro-9,10-dihydroxybenzo-fluoranthene is described.The key steps in this preparation are the Wittig reaction of acenaphthenequinone with (3-methoxyphenethyl)triphenylphosphonium bromide and the cyclization-dehydration of the intermediate, forming 10-methoxybenzofluoranthene exclusively.The synthesis of trans-2,3-dihydro-2,3-dihydroxybenzo-fluoranthene was accomplished through the intermediacy of 1,12c-dihydrobenzofluoranthen-3(2H)-one.This ketone was converted to its α-phenylseleno derivative which underwent selenoxide elimination in basic hydrogen peroxide, forming benzofluoranthene-2,3-dione directly.In each synthesis reduction of the appropriate quinone with potassium borohydride afforded the desired dihydrodiol.