CHIRAL RECOGNITION BY CYCLODEXTRINS - THE INTERACTION OF NARINGIN WITH BETA-CYCLODEXTRIN

Complex formation between naringin, 1, the bitter component of grapefr uit, and beta-cyclodextrin has been studied by H-1 NMR spectroscopy. D ifferential binding of the diastereoisomers of 1 to a polymer supporte d beta-cyclodextrin column allowed partial separation of the isomers a nd a full assignment of the H-1 NMR spectrum of the mixture to be made . In aqueous solution, one diastereoisomer binds to beta-cyclodextrin approximately 1.7 times more strongly than the other. The interaction occurs by inclusion of the aromatic ring B, but substantial chemical s hift changes are also observed for certain protons in the disaccharide unit of 1. Comparison of NMR data for the inclusion complex of the ag lycone naringenin, 2, suggests that the disaccharide unit is an import ant factor in the chiral recognition of 1 by beta-cyclodextrin.