Mono-6-Tosyl-ß-Cyclodextrin: Preparation, Hydrolysis and Self-Inclusion Studies in Aqueous Solution

The key step to attach functionnal groups on the primary hydroxyls of CD’s is a selective sulfonation to afford a monotosyl derivative. The preparation method and substitution pattern of the popular sulfonated CD’s are still unclear. Two major methods have been described in alkaline aqueous solutions1-3 or organic solvents4-5. Using pyridine as solvent leads mainly to mono-6-tosyl-6-deoxy-s-cyclodextrin but the final product is contaminated with di- or tri-tosyl-s-CD derivatives. Conversely, in aqueous solution only mono-6-tosyl-6-deoxy-s-cyclodextrin is formed but with a relatively poor yield (less than 15%).