Synthesis of alpha-GalNAc thioconjugates from an alpha-GalNAc mercaptan.

A variety of functionalized thioglycosides and other derivatives (10-24) of 2-acetamido-2-deoxy-1-thio-alpha-D-galactopyranose have been prepared in good yields and with high anomeric purities by S-substitution reactions of the sulfide anion or sulfur-centered radical from mercaptan 6. Given the importance in nature of the alpha-GalNAc 1-O-linkage, and the greater chemical and biological stability of the corresponding 1-S-linkage, these thioconjugates may find application in studies of synthetic vaccines, enzyme inhibitors, glycomimetic scaffolds, and other complex carbohydrate systems.