- Synthesis of lipo-chitooligosaccharide analogues and their interaction with LYR3, a high affinity binding protein for Nod factors and Myc-LCOs
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Lipo-chitotetrasaccharide analogues where one central GlcNAc residue was replaced by a triazole unit have been synthesized from a derivative obtained by chitin depolymerization and a functionalized N-acetyl-glucosamine via the copper-catalyzed azide-alkyn
- Berthelot, Nathan,Brossay, Antoine,Gasciolli, Virginie,Bono, Jean-Jacques,Baron, Aurélie,Beau, Jean-Marie,Urban, Dominique,Boyer, Fran?ois-Didier,Vauzeilles, Boris
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p. 7802 - 7812
(2017/10/06)
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- Synthesis of 12 Stereochemically and Structurally Diverse C-Trisaccharides
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Cell surface carbohydrates and their analogs may be used to study the cellular interactions responsible for adhesion to pathogenic bacteria, viruses, and other cells and may represent leads for drug discovery. We have generated 12 C-trisaccharides (7-18) as potential inhibitors for the cell surface proteins of the bacterium Helicobactor pylori. The strategy used has resulted in the generation of C-trisaccharides structures that are represented by the formula Fuc-α(1-2)-hexose-(1-3)-GlcNAc where each of the 12 compounds possesses a central sugar that has been systematically replaced with stereochemically diverse structures, including D and L sugars, through de novo synthesis. This aroach relies upon an organometallic coupling of terminal monosaccharides 19 and 20 to prepare a "disaccharide" in a convergent manner. This intermediate is then divergently derivatized to form a variety of structural analogs about the central hexose. For the separable compounds, the assignment of stereochemistry was done using standard NMR techniques. In cases where inseparable diastereomeric mixtures were generated, we have described a novel recursive stereochemical deconvolution strategy. This recursive strategy is demonstrated in the diastereoselective synthesis of trisaccharides 14, subsequent to its initial rapid synthesis as a component of a diastereomeric mixture. Biological assays of these compounds should provide an insight into the binding requirements of carbohydrate receptors.
- Sutherlin, Daniel P.,Armstrong, Robert W.
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p. 5267 - 5283
(2007/10/03)
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- 1,3,4,6-Tetra-O-acetyl-2-chloroacetamido-2-deoxy-β-D-glucopyranose as a glycosyl donor in syntheses of oligosaccharides
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1,3,4,6-Tetra-O-acetyl-2-chloroacetamido-2-deoxy-β-D-glucopyranose was tested as a glycosyl donor for oligosaccharide synthesis via ferric chloride-catalyzed coupling reaction.Glycosyl acceptors tried (6 in all) were O-benzyl-protected D-galactosides having free OH groups at positions 3 and 4, respectively, and similarly protected glycosides of D-glucose and 2-acetamido-2-deoxy-D-glucose unsubstituted on O-4.Existing syntheses of all the acceptors were improved, in four instances by exploitation of Garegg and Hultberg's cyanoborohydride procedure for the conversion 4,6-O-benzylidene -> 6-O-benzyl .Good to excellent yields of β-linked disaccharides were obtained from the galactoside and glucoside acceptors, but with allyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside, stereoselectivity was lost (α:β-ratio 1:2).Allyl and benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-β-D-glucopyranosides gave, respectively, the allyl and benzyl β-glycosides of the donor as major products.A mechanism is proposed for this transglycosidation reaction.The N-chloroacetyl groups in the disaccharide products were readily converted into N-acetyl by reduction with zinc-acetic acid.
- Dasgupta, Falguni,Anderson, Laurens
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p. 239 - 255
(2007/10/02)
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- The chemical synthesis of O-alpha-L-fucopyranosyl-(1 goes to 2)-O-beta-D-galactopyranosyl-(1 goes to 3)-O-[alpha-L-fucopyranosyl-(1 goes to 4)]-2-acetamido-2-deoxy-D-glucopyranose, the Lewis b blood-group antigenic determinant.
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An approach has been developed for the rapid synthesis of benzyl 2-acetamido-2-deoxy-3-O-beta-D-galactopyranosyl-beta-D-glucopyranoside (5). Disaccharide 5 was per(trimethylsilyl)ated, to provide the fully protected trimethylsilyl (Me3Si) derivative which
- Rana,Barlow,Matta
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p. 231 - 239
(2007/10/02)
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