N-Thiodiglycoloyl derivatives of glucosamine as glycosyl donors

N-Thiodiglycoloyl (TDG) protection of O-acetylated glucosamine could be rea dily carried out with thiodiglycolic anhydride and then treatment with acet ic anhydride in pyridine. Ensuing reaction with hydrazinium acetate and the n base-catalyzed activation with trichlorocetonitrile afforded N-TDG protec ted glucosamine donor 3. Glycosylation of accepters 8 and 5 in dichlorometh ane with TMSOTf as the catalyst gave beta-glycosides 6 and 9 in high yields . For TDG cleavage MeONa/MeOH treatment followed by radical desulfurization with Bu3SnH/AIBN and reacetylation with Ac2O/pyridine was employed, thus g iving N-acetyl glucosamine containing compounds 7 and 10 in a convenient, h igh-yielding procedure. (C) 2000 Elsevier Science Ltd. All rights reserved.