1H NMR Study of the Regioisomers of Primary O-Di- and Trisubstituted α-Cyclodextrins

The regioisomers of bis- and tris[C(6)-O-sulfonylated] α-cyclodextrins were converted in satisfactory yields to the corresponding C(6)-pyridinio derivatives, which afforded the characteristic splitting patterns of 1H NMR signals available for a regioisomer determination. Electrostatic repulsive interactions between the positively charged pyridinio groups play an important role in the remarkable splitting of the 1H NMR signals observed for some regioisomers.