IMPROVED METHOD FOR THE PREPARATION OF POLY[N5-(2-HYDROXYETHYL)-L-GLUTAMINE] BY AMINOLYSIS OF POLY-GAMMA-BENZYL-L-GLUTAMATE)

This paper describes the synthesis of poly[N5-(2-hydroxyethyl)-L-gluta mine] (PHEG) by the aminolysis of poly(gamma-benzyl-L-glutamate) (PBG) with 2-aminoethanol. The effects of the temperature and addition of t he bifunctional catalyst, 2-hydroxypyridine (2-HP), on the kinetics of aminolysis were studied. The results suggest that the aminolysis reac tion takes place much faster with increasing temperature and an increa sing amount of added catalyst. Moreover, chain scission, due to aminol ysis of the amide bonds of the polymer backbone, can be minimized by t he addition of the appropriate amount of 2-hydroxypyridine. These data demonstrate the feasibility of the described method to prepare PHEG d erivatives with well controlled molecular weights.