Synthesis and chiro-optical properties of copolymers from N-Boc-O-methacryloyl-(S)-serine benzhydryl ester and methyl methacrylate

Abstract

The synthesis of the homopolymer of N-Boc-O-methacryloyl-(S)-serine benzhydryl ester and a series of copolymers with methyl methacrylate by benzoyl peroxide-induced radical polymerisation is reported. All of the polymers are optically active, but both the magnitude and the sign of the specific rotation varies with the composition of the polymers. At low incorporations of the serine-derived monomer, the specific rotation is positive, but a maximum value is reached at approximately 35% serine-derived monomer incorporation. As more serine-derived monomer is incorporated into the polymers, the specific rotation falls and becomes negative at 70% serine-derived monomer incorporation. The molecular weight and molecular weight distributions of the copolymers were determined by GPC. The protecting groups could be removed from the copolymers, giving a class of zwitterionic, chiral polymers some of which are soluble in aqueous solvents.