Absolute Configurations of K-Region Epoxide Enantiomers of 3-Methylcholanthrene, Benzanthracene, and Benzopyrene

Article abstract of DOI:10.1021/ac00149a011

The absolute configurations of K-region epoxide enantiomers of 3-methylcholanthrene, benzanthracene, and benzopyrene have been determined via their monomethyl ether derivatives.Methoxylation of each racemic or enantiomeric epoxide by sodium methoxide resulted in a pair of monomethyl ether derivatives, which were separated by normal-phase high-performance liquid chromatography (HPLC).The position of the methoxy group was determined by products formed by acid-catalyzed dehydration and/or demethanolization of each monomethyl ether derivative.Enantiomers of each epoxide and its methoxylated derivatives were resolved by at least two of the four Pirkle chiral stationary phase HPLC columns utilized in this study.The absolute stereochemistries of enantiomeric monomethyl ether derivatives were established by comparing their circular dichroism spectra with those of enantiomeric monomethyl ether derivatives derived from trans dihydrodiol enantiomers of known absolute configurations.The absolute configuration of each epoxide enantiomer was deduced from the location of the methoxy group and the absolute configuration of enantiomeric monomethyl ether derivatives.Results indicate that the method described is useful in general for the determination of absolute configurations of K-region epoxide enantiomers of polycyclic aromatic hydrocarbons.