Reinvestigation of <i>N</i>,<i>N</i>-Diacetylimido-Protected 2-Aminothioglycosides in <i>O</i>-Glycosylation: Intermolecular Hydrogen Bonds Contributing to 1,2-Orthoamide Formation
N,N-Diacetylimido protection of 2-aminoglycosides is an elegant strategy but has had limited applications due to unexpected side reactions in glycosylation. We found that high acid concentrations could diminish the side reactions. We observed intermolecular hydrogen bonding among alcohols and acids could disrupt. Assuming that intermolecular hydrogen bonding accelerates the formation of 1,2-orthoamides
N-Thiodiglycoloyl derivatives of glucosamine as glycosyl donors
作者:Julio C Castro-Palomino、Richard R Schmidt
DOI:10.1016/s0040-4039(99)02136-x
日期:2000.1
anhydride and then treatment with acetic anhydride in pyridine. Ensuing reaction with hydrazinium acetate and then base-catalyzed activation with trichlorocetonitrile afforded N-TDG protected glucosamine donor 3. Glycosylation of acceptors 8 and 5 in dichloromethane with TMSOTf as the catalyst gave β-glycosides 6 and 9 in high yields. For TDG cleavage MeONa/MeOH treatment followed by radical desulfurization
Procédé de synthèse organique d'oligosaccharides, correspondant à des fragments de muco-polysaccharides naturels, nouveaux oligosaccharides obtenus et leurs applications biologiques
申请人:D.R.O.P.I.C. (Société Civile)
公开号:EP0084999A1
公开(公告)日:1983-08-03
Procédé de synthèse organique d'oligosaccharides constituant ou correspondant à des fragments de muco-polysaccharides acides dans lequel on fait réagir deux composés constitués ou terminés respectivement par des motifs de structure sucre aminé et des motifs de structure acide uronique. Ces motifs étant substitués spécifiquement.
Ce procédé conduit à des oligosaccharides utilisables notamment en thérapeutique.