LIQUID-CHROMATOGRAPHIC SEPARATION OF THE ENANTIOMERS OF ANTIHISTAMINIC 3,3'-DI(1,3-THIAZOLIDIN-4-ONE) DERIVATIVES WITH 2 AND 4 STEREOGENIC CENTERS

The enantiomers of anti-inflammatory and antihistaminic 3,3'-(1,2-ethanediyl)bis(2-aryl-1,3-thiazolidin-4-one) derivatives possessing two stereogenic centres were separated on Chiralcel OD stationary phase without derivatization. The meso form was also well separated from the enantiomers. The good resolution afforded a milligram-scale separation and subsequent measurement of the circular dichroism spectra of an enantiomeric pair. Addition of racemic alpha-mercaptopropionic acid to the N,N'-dibenzylideneethylenediamine yielded ten possible stereoisomers with four stereogenic centres. Two centres (2 and 2') bear the same groups; the other two (5 and 5') also bear the same groups, but these are different from the groups at 2 and 2'. In this situation four enantiomeric pairs and two meso forms exist; all of them were separated and identified using a Chiralpak AD column.