Polysaccharides reductive-cleavage

J. S. Sherman and G. R. Gray, Studies of model compounds for the analysis of ester-containing polysaccharides by the reductive-cleavage method, Carbohydr. Res., 231 (1992) 221-235. 

Conditions for use in the reductive-cleavage analysis of permethylated polysaccharides (Bp3.0Et2 or TmsOTf, 1,2-dichloroethane, 70 °C) wherein all 2-deoxy-2-acetamido-A-methyl-hexopyranoside residues are converted into oxazolinium ions, e.g. 68, which give methyl glycosides, e.g. 69, on quenching... 

In a rapid synthesis of authentic standards for the reductive-cleavage method of polysaccharide structural analysis, the eight positional isomers of partially... 

The reductive cleavage method is one of the important tools for determining the structure of polysaccharides [77]. Various aspects of the method have been studied extensively [78-88]. So far, the investigation has concentrated mostly on the variation of polysaccharides and catalysts, while triethylsilane and dichloromethane are employed as the reducing agent and solvent, respectively. 

In connection with the analysis of ollgo- and polysaccharides by the permethylation - "ionic hydrogenation" procedure, a series of partially methylated anhydro-D-alditol acetates has been prepared by reductive cleavage of permethyl and partially methylated methyl glycosides and a library of capillary g.c. retention times and e.l.- and c.i.-m.s. data compiled. The usefulness of this data was demonstrated in the analysis of a microgram quantity of a... 

The relative stability of various pyruvate ketal substituents in polysaccharides to either permethylation-methanolysis or permethylation-reductive cleavage (EtjSiH - MejSiOTf) has been... 

Reductive cleavage of the permethylated polysaccharide is recommended as a gentle alternative to hydrolysis. In this process, partially methylated anhydroalditolacetates are formed as shown in Fig. 4.42, using a galactomannan as an example. Conclusions about the structure of the polysaccharide can be drawn from the result of the qualitative and quantitative analysis, which is carried out by gas chromatography/mass... 

The synthesis of all positional isomers of partially methylated-acetylated or methylated-benzoylated derivatives of 1,4-anhydro-D-xylitol, 1,4-anhydro-L-fucitol, 1,4-anhydro-D-ribitol, 1,5-anhydro-D-mannitol, 1,5-anhydro-D-gJu-citol, and IjS-anhydro-D-galactitoP" have been described. The compounds should be useful as standards for determining the primary structure of polysaccharides after reductive cleavage. 

Pectinase Pectinesterase Pectinlyase Polygalacturonase Pectolytic Enzymes Cleavage of Plant (a-1,4) Polysaccharides Aspergillus Niger Disintegration of Plant Tissue. Reduction of Macerate Viscosity. Improved Extracta-bility of Juice-bound Flavours... 

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