Abstract
Abstract To understand conformation difference between hyaluronic acid disaccharide and it's analoges, hyaluronic acid disaccharide (GlcAβ1-3GlcNAcβ1-SPhCH3) and it's related 6'-O-sulfated (6'-O-sulfate-Glcβ1-3GlcNAcβ1-SPhCH3) and 6-OH (Glcβ1-3GlcNAcβ1-SPhCH3) analogues were synthesised. Glycosylation using thioglycoside as acceptor and glycosylimidate as donor was performed with trimethylsilyltriflate as the promoter. For the synthesis of hyaluronic acid tetrasaccharide, we found that using TBDPS group as a protecting group at glucose 6' position, the glycosylation between disaccharide donor and acceptor didn't proceed. When the protecting group was changed from TBDPS group to benzyl group, thw desired product still could not be obtained. We found that the type of protecting group at Glc 2' and 3' position would deeply affect the 4-OH for proceeding glycosylation.