Synthesis of the Major Metabolic Dihydrodiols of Benzo[j]fluoranthene

Syntheses are described for the major dihydrodiol metabolites of benzo[j]fluoranthene. irans-4,5-Dihydro-4,5-dihydroxybenzo[j]fluoranthene was prepared via 9-methoxy-1 lif-benzo[a]fluorene. Two of the intermediates in this synthetic sequence, 4-hydroxybenzo[j]fluoranthene and benzo[j]fluoranthene-4,5-dione, are also suspect metabolites of the parent hydrocarbon. An improved synthesis for trons-9,10-dihydro-9,10-dihydroxybenzo[j]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-methoxybenzo[j]fluoranthene exclusively. The synthesis of trons-2,3-dihydro-2,3-dihydroxybenzo[j]fluoranthene was accomplished through the intermediacy of 1,12c-dihydrobenzo[j]fluoranthen-3(2if)-one. This ketone was converted to its -phenylseleno derivative which underwent selenoxide elimination in basic hydrogen peroxide, forming benzo[j]fluoranthene-2,3-dione directly. In each synthesis reduction of the appropriate quinone with potassium borohydride afforded the desired dihydrodiol.