- Efficient synthesis of meningococcal X polysaccharide repeating unit (n-acetylglucosamine-4-phosphate) as analytical standard for polysaccharide determination
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Serogroup X Neisseria meningitidis (MenX) is emerging in many African countries as a major cause of meningococcal meningitis, but no preventative therapy against this serogroup is yet available. N-Acetylglucosamine-4-phosphate (4P-GlcNAc), the monomeric repeating unit of MenX polysaccharide, is an important requirement for the development of an analytical method specific for MenX polysaccharide quantification. At the moment, this compound is not commercially available. Herein an efficient preparation of this monosaccharide is reported.
- Adamo, Roberto,Micoli, Francesca,Proietti, Daniela,Berti, Francesco
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- MENINGOCOCCUS SEROGROUP X CONJUGATE
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The invention provides a conjugate of a Neisseria meningitidis serogroup X capsular polysaccharide and a carrier molecule. The conjugate is typically made by (a) oxidising a primary hydroxyl group in the capsular polysaccharide, to give an oxidised polysaccharide with an aldehyde group; and (b) coupling the oxidised polysaccharide to a carrier molecule via the aldehyde group, thereby giving the conjugate. The conjugate may be part of an immunogenic composition. This composition may comprise one or more further antigens, particularly capsular polysaccharides from serogroups A, W135, C and Y and conjugated forms thereof. The composition may be in an aqueous formulation. The composition is useful as a vaccine, e.g. for raising an immune response in a mammal. The invention also provides processes for making the conjugate.
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- Design and synthesis of unnatural heparosan and chondroitin building blocks
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Triazole linked heparosan and chondroitin disaccharide and tetrasaccharide building blocks were synthesized in a stereoselective manner by applying a very efficient copper catalyzed azide-alkyne cycloaddition (CuAAC) reaction of appropriately substituted
- Bera, Smritilekha,Linhardt, Robert J.
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p. 3181 - 3193
(2011/06/24)
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- Syntheses of model oligosaccharides of biological significance. XII. Synthesis, NMR, and conformational analysis of trideuteriomethyl 4-O-(β-D-mannopyranosyl)-2-acetamido-2-deoxy-β-D-glucopyranoside: the use of DEPT 1H to 13C transfer for T1 measurements and NOE assignments of ...
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The title disaccharide Manp(β1-4)GlcpNAcβ1-OCD3 has been prepared by a short synthetic sequence through the inversion of configuration from gluco to manno involving benzyl Glcp(β1-4)GlcpNAc.The disaccharide was subjected to detailed high-field 1H and 13C NMR study.First, conventional and 2D spectra were run to afford a complete set of assigned spectral parameters.Next, steady-state 1H- NOE and 1H, 13C spin lattice relaxation experiments were performed to infer dynamic spectral data related to molecular conformation.Owing to tight couplings and signal overlaps in the 1H spectrum, proton relaxation and selected NOE data were obtained via 13C NMR after transfer of the actual, non-equilibrium, proton magnetization to the 13C frequency domain.Using this experimental approach it has been found that T1's for Manp H-4 and GlcpNAc H-2 were substantially longer than those of the other sugar ring protons, and that the principal interresidue dipolar contact in Manp(β1-4)GlcpNAcβ1-OCD3 takes place between Manp H-1 and GlcpNAc H-4.Subsequently, a conformational analysis of the disaccharide was executed by means of a semiempirical method comparing Boltzman-averaged computed observables with experimental T1 and NOE values.The results suggest that the disaccharide has substantial conformational flexibility.Its exo-anomeric-stabilized conformational minimum at approximately Φ = +50 deg (Ψ = 0 +/- 10 deg) of the glycosidic rotational angle is significantly populated but this global minimum does not represent the only rotational form available to the molecule.
- Lee, Ho Huat,Congson, Ligaya N.,Whitfield, Dennis M.,Radics, Lajos R.,Krepinsky, Jiri J.
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p. 2607 - 2617
(2007/10/02)
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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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- Phosphorylated Sugars. Part 25. Synthesis and Behaviour in Acidic Media of 2-Acetamido-2-deoxy-D-glucose 4- and 6-Phosphates and of a 'Lipid A' Analogue
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With the aid of 2-acetamido-2-deoxy-D-glucose 4- and 6-phosphates and 2-amino-2-deoxy-D-glucose-6-phosphate, for all of which new and efficient syntheses are described, it has been shown that during treatment of 2-acetamido-2-deoxy-D-glucose 4-phosphate a
- Szabo, Patricia
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p. 919 - 924
(2007/10/02)
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- The synthesis of 2-acetamido-2-deoxy-4-O-beta-D-mannopyranosyl-D-glucose.
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Condensation of 4,6-di-O-acetyl-2,3-O-carbonyl-alpha-D-mannopyranosyl bromide with 2-amino-2-N,3-O-carbonyl-5.6-O-isopropylidene-D-glucose diethyl acetal gave, unexpectedly, 2-amino-2-N,3-O-carbonyl-2-deoxy-4-O-(4,6-di-O-acetyl-2,3-O-carbonyl-alpha-D-mannopyranosyl)-5,6-O-isopropylidene-D-glucose diethyl acetal, futher transformed, by de-esterification followed by acetylation, into the previously known 2-amino-2-N,3-O-carbonyl-2-deoxy-5,6-O-isopropylidene-4-O-alpha-D-mannopyranosyl-D-glucose diethyl acetal and its tetra-O-acetyl derivative. Benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranoside was condensed with 2-O-acetyl-3,4,6-tri-O-benzyl-beta-D-glucopyranosyl bromide to give benzyl 2-acetamido-4-O-(2-O-acetyl-3,4,6-tri-O-benzyl-beta-D-glucopyranosyl)-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranoside. Removal of the 2-O-acetyl group, followed by oxidation with acetic anhydridedimethyl sulfoxide, gave a beta-D-arabino-hexosid-2-ulose (25). After reduction with sodium borohydride, removal of the benzyl groups gave crystalline 2-acetamido-2-deoxy-4-O-beta-D-mannopyranosyl-D-glucose (27). The anomeric configuration of the glycosidic linkage was ascertained by comparison with the alpha-D-linked disaccharide.
- Shaban,Jeanloz
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p. 115 - 127
(2007/10/10)
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