Permethylation of Oligomeric and Polymeric Carbohydrates and Quantitative Analysis of the Cleavage Products

Methylation of mono-, oligo-, and polysaccharides with methyl iodide/barium oxide or dimethyl sulfate/barium hydroxide in dimethyl sulfoxide as solvent rapidly leads to high degrees of methylation. Depending on the structure and solubility of the substrate, permethylation can be achieved either in one operation or by repetition of the same treatment. Procedures of permethylation of various carbohydrates are given. The methyl glycosides obtained on methanolysis can be separated and determined quantitatively by gas chromatography. The preparation of separating columns with minimum retention for this purpose is described. Pullulan was shown to have the structure of a completely linear polymer of maltotriose units connected by α-1→6-linkages. – In addition the gaschromatographic identification of methyl ethers of glucosamine and galactosamine is reported