- Phenyl 2-azido-2-deoxy-1-selenogalactosides: a single type of glycosyl donor for the highly stereoselective synthesis of α- and β-2-azido-2-deoxy-d-galactopyranosides
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Efficient glycosylation with phenyl 2-azido-2-deoxy-1-seleno-α-d-galactosides of glycosyl acceptors with different reactivities has been developed. The reaction provided glycosides of 2-azido-2-deoxy-d-galactose in good to high yields. The stereochemical outcome of the glycosylation of reactive acceptors (3-trifluoroacetamidopropanol and methyl 2,3-O-isopropylidene-α-l-rhamnopyranoside) can be broadly varied from complete β- to high α-selectivity by changing the reaction solvent, promoter and protecting groups in the donor, while the glycosylation of less reactive allyl 2,2′,3,3′,6,6′-hexa-O-benzoyl-β-lactoside afforded the corresponding α-glycosides exclusively.
- Khatuntseva, Elena A.,Sherman, Andrey A.,Tsvetkov, Yury E.,Nifantiev, Nikolay E.
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p. 708 - 711
(2016/01/26)
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- Synthesis of terminal disaccharide of Forssman's antigen and some of its analogs as spacered glycosides and free disaccharides
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Spacered terminal disaccharide of Forssman's antigen GalNAcα1-3GalNAcβ1-Osp, its analog GalNAcα1-3GalNAcα1-Osp, and disaccharides Galβ1-3GalNAcβ1-Osp and Galα1-3GalNAcα1-Osp [where sp denotes the (CH2)3NHCOCF3 spacer] were synthesized. Spacered disaccharides were obtained from the (3-trifluoroacetamidopropyl)-2-acetamido-4,6-O-benzylidene-2-deoxy-β-D- galactopyranoside and its α-and β-analogs in which the 2-azido group was substituted for the 2-acetamido group. The azide glycosyl acceptors gave higher yields of the disaccharides. Azide glycosyl acceptors were prepared by the stereoselective glycosylation of 3-trifluoroacetamidopropanol with a mixture of 1-O-acetates of the 2-azido-3,4,6-tri-O-acetyl-2-deoxy-D-galactopyranose anomers in the presence of Lewis acids. Disaccharides Galα1-3GalNAc and GalNAcα1-3GalNAc were obtained from the benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-α-D-galactopyranoside.
- Ovchinnikova,Ter-Grigoryan,Pazynina,Bovin
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