Sugar methyl ethers

Relative Retentions op Isomeric Sugar Methyl Ethers - ... 

Classification of the polysaccharide type is achieved fundamentally by hydrolysis to identifiable sugars, and by methylation analysis, in which the cleavage products from the permethylated polysaccharide are identified and assayed, after conversion to alditol acetates, acetylated aldononitriles, or other derivatives, by GC and GC-MS. Methanolysis of the permethylated polysaccharide and conversion to TMS derivatives is an alternative. The proportions of monosaccharides and their linkage modes are deduced from the molar quantities of sugar methyl ethers derived from the processed polysaccharide... 

Dichloromethyl methyl ether may be employed preparatively in various ways. Thus it effects the replacement of carbonyl and hydroxyl oxygens by chlorine,11 and may be used in the preparation of a-acetochlorosugars 12 and acid chlorides, particularly those derived from acetylated monocarboxylic acid sugars 12 13... 

D-Xylose, which is one of the most abundant sugars in plant polysaccharides, is a rare component of bacterial polysaccharides. It is found in the LPS of Type 1 Neisseria gonorrhoeae strain" GC 6. L-Xylose and its 3-methyI ether are components of the LPS of Pseudomonas maltophila strain NCTC 10257, and are j -pyranosidic. The d- and L-sugars, and different methyl ethers of these, have also been found in the LPS of some photosynthetic bacteria."... 

The glycosyl-linkage compositions of our three RG-II preparations were similar (Table 2) and corresponded to the relative sugar molar ratios obtained from compositional (TMS derivatives) analyses indicating that methylation was complete. Almost all the methyl ethers obtained could be attributed to known residues of the RG-II molecule (Figure 1) and our data were in accordance to that previously reported for RG-II from different plant origins [3,8,12,20,26]. The relative molar ratios of these "characteristic" methyl ethers (calculated on the basis of 1 residue of 3,4-linked fucose) were almost all in stoichiometric amounts (Table 3), confirming thus that our three preparations corresponded to the accepted model for RG-II. 

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