title: Absolute configuration of cis-5,6-dihydrodiol enantiomers derived from helical conformers of 1,12-dimethylbenz[a]anthracene.
abstract: 1,12-Dimethylbenz[a]anthracene (1,12-DMBA) cis-5,6-dihydrodiol was synthesized by oxidation of 1,12-DMBA with osmium tetroxide in pyridine in low yield (less than or equal to 3%) and was purified by sequential use of reversed-phase and normal-phase HPLC. Two pairs of 1,12-DMBA cis-5,6-dihydrodiol enantiomers, derived from P (right-handed helix) and M (left-handed helix) conformers, were eluted as a single chromatographic peak on both reversed-phase and normal-phase HPLC. However, these four enantiomers were resolved by sequential use of two chiral stationary phase (CSP) HPLC columns. CSP (Pirkle type I) columns were packed with either (R)-N-(3,5-dinitrobenzoyl)phenylglycine or (S)-N-(3,5-dinitrobenzoyl)leucine, which is ionically bonded to gamma-aminopropylsilanized silica. Absolute configurations of enantiomers were determined by comparing their circular dichroism spectra with those of conformationally similar cis-5,6-dihydrodiol enantiomers of 4-methylbenz[a]anthracene and 7,12-dimethylbenz[a]anthracene with known absolute stereochemistry.
authors.affiliation: Department of Pharmacology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799.
authors.forename: S K
authors.initials: SK
authors.lastname: Yang
authors.forename: M
authors.initials: M
authors.lastname: Mushtaq
authors.forename: P P
authors.initials: PP
authors.lastname: Fu
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000032:analysis / Q000031:analogs & derivatives; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D013058:Mass Spectrometry; D008968:Molecular Conformation; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
chemical_list: C013956:7,12-dimethylbenz(a)anthracene-dihydrodiol; D015127:9,10-Dimethyl-1,2-benzanthracene