N-functionalization of chitosan with bis-O-glycosylated derivative of 2,2-bis(methylol)propionic acid

A glycosylated 2,2-bis(methylol)propionic acid (bis-MPA) derivative as a versatile glycodendritic building block was synthesized by direct O-glycosylation of benzyl protected bis-MPA with d-glucose pentaacetate. After removal of the benzyl protection group by hydrogenation, the obtained bis-O-glycosylated bis-MPA unit with free carboxyl group was applied for modification of trityl protected chitosan by amidation. The removal of the 6-O-trityl protection group on chitosan backbone under acidic conditions yields acetyl protected glycosylated chitosan that forms gel in water. The acetyl protection group of d-glucose was removed under alkaline conditions to form glycosylated chitosan which is water-soluble at physiological conditions and, thus, it is suitable for further investigation as a potential carrier in drug delivery systems.