Multi-Gram Synthesis of a Hyaluronic Acid Subunit and Synthesis of Fully Protected Oligomers

Fully protected tetra-, hexa- and octasaccharides of hyaluronic acid were synthesized on a scale of several 100 mg up to gram quantities using allyl (methyl 2-O-benzoyl-3-O-benzyl-4-O-levulinoyl-beta-D-glucopyranosyluronate)-(1 -> 3)-4-O-acetyl-6-O-benzyl-2-deoxy-2-trichloroacetamido-beta-D-glucopyranoside as a key building block. This disaccharide was subjected to deprotection, then glycosylation via the trichloroacetimidate method was employed to achieve the formation of the oligosaccharides.