The enantiomers of the 5, 5-dimethyl-1-(o-aryl) barbituric and 2-thiobarbituric acid derivatives have been separated by micropreparative liquid chromatography on the Chiralcel OD-H column. The activation barriers for the conversion of one enantiomer to its counterpart (M⇄ P) have been determined upon thermal racemization of the separated enantiomers by following the intensity changes in the HPLC chromatograms with time. ...
