Two K-regions of 5-methylchrysene are sites of oxidative metabolism.

Two K-region trans-dihydrodiols were identified as products formed in the metabolism of 5-methylchrysene by liver microsomes from phenobarbital-treated male Sprague-Dawley rats. These two dihydrodiols were isolated from a mixture of metabolites by reversed-phase and normal-phase high-performance liquid chromatographies. Both K-region dihydrodiols were characterized by ultra-violet, mass, and circular dichroism spectral analyses. Chiral stationary phase high-performance liquid chromatographic analyses indicated that 5-methylchrysene 5,6-dihydrodiol and 11,12-dihydrodiol contain (S,S): (R,R) enantiomer ratios of 2:98 and 12:88, respectively. Although it is a bay-region dihydrodiol, the hydroxyl groups of 5-methylchrysene trans-5,6-dihydrodiol adopt a quasidiequatorial conformation.