Thermal polymerization of some glucofuranose derivatives

Methyl alpha,beta-D-glucofuranoside (1) and 1,2-O-isopropylidene-alpha-D-glucofuranose (2) have been polymerized thermally, using 0.1% phosphoric acid as catalyst. The resulting alcohol-insoluble polymers were analyzed by gel-permeation chromatography and methylation analysis. The two starting materials gave polymers that were very similar in molecular-weight distribution and in glycosyl-linkage composition. The proportion of furanosyl residues in the polymer, estimated by the relative proportions of furanosyl and pyranosyl residues that could be determined unequivocally by methylation analysis, was approximately 35-40%; higher than is found when glucopyranosides are polymerized, but indicating that significant furanose-pyranose isomerization had occurred during the polymerization process.