Hetero-bifunctional γ-cyclodextrins having dansylcysteine and tosyl groups at two adjacent sugar units: synthesis and determination of regio-chemistry

Ditosylation of two adjacent 6-positions of γ-cyclodextrin, subsequent mono-substitution with l-cysteine and final condensation with dansyl chloride afford the title compounds whose clockwise and counterclockwise isomers are separated from each other and their regio-chemistry is unambiguously determined by a new strategy based on the combination of enzyme degradation of the hetero-bifunctional γ-cyclodextrin to the corresponding disubstituted maltotriose and fragmentation analysis of the latter by PSD-MS technique.