PubMed · 1472756
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S Doubet, P Albersheim. 1992. CarbBank.. https://doi.org/10.1093/glycob%2F2.6.505
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A computer-assisted approach to the analysis of the structure of branched polysaccharides that contain 2,3-di-O-glycosylated alpha-rhamnopyranose and alpha-mannopyranose residues is based on evaluation of the 13C NMR spectra, using glycosylation effects and their deviations from additivity (delta delta values) at the branch points. This approach, in combination with monosaccharide and methylation analysis data, has been verified on a series of bacterial polysaccharides of known structure.
The syntheses are described of 2,3-di-O-glycosyl derivatives of methyl alpha-L-rhamnopyranoside (1-5) and alpha-D-mannopyranoside (6-9). [formula: see text] [table: see text] The deviation from additivity in 13C NMR spectra calculated for 1-9 were similar for stereochemically related trisaccharides.
Jones oxidation of suitably protected allyl beta-D-galactopyranosides and subsequent esterification were reinvestigated. Partial deprotection of the resulting D-galacturonic acid derivatives afforded compounds suitable for transformation into glycosyl acceptors. The synthesis of 2-, 3-, and 4-trityl ethers, relying on efficient differential protecting-group strategies, is described. Trityl-cyanoethylidene condensation of these trityl ethers, leading to the protected disaccharide units beta-D-GalpA-(1-->2)-D-GalpA and beta-D-GalpA-(1-->3)-GalpA with high stereoselectivity, is demonstrated. A beta-D-GalpA-(1-->4)-D-GalpA disaccharide was also prepared.