1-(o-aryl)barbituric and 1-(o-aryl)-2-thiobarbituric acid derivatives: chiral atropisomers.
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.
Oğuz
F S
FS
Department of Chemistry, Boğaziçi University, Bebek 80815, Istanbul, Turkey.
Berg
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U
Doğan
I
I