Syntheses of 2,6-O-alkyl celluloses: influence of methyl and ethyl groups regioselectively introduced at O-2 and O-6 positions on their solubility

2,6-Di-O-ethyl (2E6E) (1), 2-O-ethyl-6-O-methyl (2E6M) (2), and 6-O-ethyl-2-O-methyl (6E2M) (3) celluloses were synthesized via ring-opening polymerization of glucose orthopivalate derivatives. 2,6-Di-O-methyl cellulose (2M6M) was insoluble in any common solvents, though it was not expected. On the other hand, cellulose derivative 1 (2E6E) was soluble in chloroform. Introduced positions of alkyl groups on cellulose affected solubilities of cellulose derivatives. Their solubility in chloroform decreased in the order: polymer 1 (2E6E) > polymer 2 (2E6M) > polymer 3 (6E2M) ≫ 2M6M.