CHEMICAL MODIFICATION OF PULLULAN .2. CHLOROFORMATE ACTIVATION

The present paper describes the chloroformate activation of pullulan b y reaction with 4-nitrophenyl chloroformate. N.m.r. analysis indicated that the ester formation takes place preferentially at the C6 hydroxy groups of pullulan. It was further demonstrated that activation gives linear carbonates, aliphatic carbonates including cyclic five-membere d carbonates, and non-strained aliphatic carbonates. All of these carb onates react with amines to yield the corresponding urethane derivativ es. The 4-nitrophenyl chloroformate activation of pullulan is an easy method for obtaining amine-containing pullulan derivatives.