Metabolism of the bay-region trans-1,2-dihydrodiol of benz[a]anthracene in rat liver microsomes occurs primarily at the 3,4-double bond.

The bay-region hydroxyl groups of benz[a]anthracene (+/-)trans-1,2-dihydrodiol are known to be exclusively in quasi-axial conformations. This dihydrodiol was stereoselectively metabolized in rat liver microsomes to form two optically active 1,2,3,4-tetrahydrotetrols as the predominant products. Thus, the bay-region axial hydroxyl groups of benz[a]anthracene trans-1,2-dihydrodiol do not direct metabolism away from the vicinal 3,4-double bond.