Anionic ring-opening polymerization of a five-membered cyclic urethane derived from d-glucosamine

The anionic ring-opening polymerization of a five-membered cyclic urethane, 2-amino-4,6-O-benzylidene-2-N,3-O-carbonyl-2-deoxy-alpha,d-glucopyranoside (MBUG), which was prepared from naturally abundant d-glucosamine, was examined. Potassium tert-butoxide (t-BuOK) was the most effective initiator among the evaluated bases and produced polyurethane with the Mn of 7800 without any elimination of CO2. The equimolar reaction of MBUG and t-BuOK in the presence of CH3I produced N-methylated MBUG and suggested that the initiation reaction involves proton abstraction from the NH group. This N-methylated compound did not undergo the polymerization. Therefore, the mechanism of propagation in the ROP of MBUG should involve the proton abstraction and nucleophilic substitution of the resulting amide anion. (c) 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019