Dextrins methylation analysis

Methylation analysis of -dextrin gives 2,3,6-tri-0-methyl-D-glucose... 

A second major structural method applied to the Schardinger dextrins was methylation analysis. This method was fraught with experimental difficulties, and in a few cases it had led to rather embarrassing errors in assigning of structure. ... 

Transglycosylation seems to be the most typical and predominant reaction among the group of reactions constituting the dextrinization process. The evidence for it, as well as for the mechanism just presented, was provided by the results of methylation analysis of com British gum (see Table XIX). Incidentally, the formation of ether-type bonds was questioned. ... 

A different chemistry must be involved in the formation of pyrodextrins, that is, the dextrinization of starch in the presence of catalysts. TTie methylation analysis of various pyrodextrins " indicated this well (see Tables... 

In applying the Kuhn methylation to a pentasaccharide isolated from amylopectin a-limit dextrin, the maximum methoxyl content that French, E. E. Smith, and Whelan were able to obtain was 41.8X (theoretical, 49.5%). Quantitative analysis of the hydrolyzate showed that there was no undermethylation, and they concluded that it is essential to wash the product with cyanide after each methylation in order to eliminate chloroform-soluble impurities containing iodine. Kabat and coworkers found that a Kuhn methylation of hexosamines using silver oxide did not give interpretable results, but no problem was experienced when barium oxide was employed. 

ABSTRUCT. Some physicochemical properties of methylated g-cyclo-dextrins, i.e., heptakis(2,6-di-0-methyl)-g-cyclodextrin (DM-g-CyD) and heptakis(2,3,6-tri-O-methyl)-3-cyclodextrin (TM-3-CyD) were compared with those of natural 3 cyclodextrin (3-CyD), Inclusion behaviors of 3 CyD and methylated 3 CyDs in water and in solid state were studied by solubility analysis, spectroscopies (UV, CD, C-NMR and IR),... 

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