STRUCTURAL ASPECTS OF PERMETHYLATED CYCLODEXTRINS AND COMPARISON WITHTHEIR PARENT OLIGOSACCHARIDES, AS DERIVED FROM UNEQUIVOCALLY ASSIGNEDH-1 AND C-13 NMR-SPECTRA IN AQUEOUS-SOLUTIONS

The complete assignments of the H-1 and C-13 NMR spectra of alpha-, be ta- and gamma-cyclodextrins (CDs) and their permethylated derivatives were derived from dedicated experiments. Existing literature data were complemented with detailed analyses, including unequivocal assignment of the methoxy groups, The structures of the macrocycles in solution, as derived from the NMR data, resemble those in the solid state, The increased distortions observed for the larger permethylated CDs are ex pected to affect seriously their complexing ability.