Preparation and characterization of some alpha-D-glucans containing 3,6-anhydro D-glucose.

Alfa-D-glucans containing a 3,6-anhydro D-glucosyl residue were prepared from three kinds of alpha-D-glucan (elsinan, pullulan, and amylose), and the physical properties of these 3,6-anhydro glucans were examined. The method employed for introducing the 3,6-anhydro linkage into a D-glucosyl residue involved sulfation of the O-6 position with dimethylsulfoxide-sulfur trioxide complex and a subsequent alkali treatment of the resulting partially sulfated glucan. This introduction of the 3,6-anhydro linkage caused a decrease in viscosity of the original polysaccharides and made them resistant to the action of hydrolytic enzymes. Hydrolysis of the 3,6-anhydro glucans with dilute acid afforded several oligosaccharides whose reducing end was 3,6-anhydro D-glucose.