Polycondensation of D-Glucose with Polyphosphoric Acid and Its Ester in Polar So l v entt

Abstract

Polycondensation of D-glucose has been carried out in dimethyl sulfoxide (DMSO) and N, N-dimethylformamide (DMF) with polyphosphoric acid (PPA) and polyphosphoric ester (PP E)as condensation agents. A colorless synthetic glucan was obtained in high yield by the reaction of 20 g of anhydrous ID-glucose with 30 g of the condensation agent (PPA or PPE) in 50ml of solvent (DMSO or DMF) at 50°C for 7 h. DMSO proved to be better than DMF for obtaining the colorless synthetic glucan in high yield. For example, the characteristics of the synthetic glucan which was obtained in the reaction mixture of DMSO-PPE were as follows: the degree- of polymerization; 28, [α]_D²²+26 8.0° (c=1, H₂O), combined phosphorus; 0.70%and yield.; 63%. The structure of the synthetic glucan was studied by the periodate oxi dation gnd-the Smith degradation. The amount of the formic acid formed was relatively hi gh when compared with the amount of the consumed periodate and the amount of the glycerol fo rmed was also high in the Smith degradation. The results suggest that the synthetic glucan has many nonreducing end groups and, therefore, many branched chains. The polycondensation reactions with the use of PPA and PPE in DMSO were found to be fair different from each other. Studies on the Synth esis of Polysaccharide. II.