Synthesis of Two Hyaluronan Trisaccharides

The synthesis of two hyaluronan trisaccharides, methyl O-(β-d-glucopyranosyluronic acid)-(1,3)-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1,4)-O-β-d-glucopyranosiduronic acid and methyl O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1,4)-O-β-d-glycopyranosyluronic acid)-(1,3)-O-(2-acetamido-2-deoxy-β-d-glucopyranoside, are described. Construction of the target molecules was achieved though a combination of the phenyl sulfoxide and trichloroacetimidate glycosylation methodologies. This is the first report on the synthesis of the β-methyl derivatives, which represent the smallest fragments that incorporate all the structural features of polymeric hyaluronan.