title: 1-(o-aryl)barbituric and 1-(o-aryl)-2-thiobarbituric acid derivatives: chiral atropisomers.
abstract: Several 1-(o-aryl)barbituric and -2-thiobarbituric acid derivatives were proven to be chiral in their conformational ground states due to the hindered rotation about the C(aryl)-N(1) bond, by observation of diastereotopic groups (H or CH3) at 5-position of the heteroring by 1H and 13C NMR. Some of the enantiomers were semipreparatively enriched by liquid chromatography on triacetylcellulose or on cellulose tris-(3,5-dimethyl)-phenylcarbamate (chiralcel OD-H). Circular dichroism spectra of the enriched enantiomers have been examined with reference to their stereostructures.
authors: Department of Chemistry, Boğaziçi University, Bebek 80815, Istanbul, Turkey.
authors: F S
authors: FS
authors: Oğuz
authors: U
authors: U
authors: Berg
authors: I
authors: I
authors: Doğan