POLYMERIZATION REACTIVITY AND CHIROPTICAL PROPERTY OF N-MALEOYL-L-PHENYLALANINE CYCLOHEXYL ESTER

A new type of optically active N-maleoyl-L-phenylalanine cyclohexyl ester (CHPAM) was synthesized from maleic anhydride, L-phenylalanine, and cyclohexanol. Radical and anionic polymerizations were carried out in several solvents at 60 degrees C and 0 degrees C, respectively, to obtain optically active polymers. Number average molecular weights (($) over bar M(n)) of the homopolymers were 4.4 x 10(3) to 1.5 x 10(4). Specific optical rotations ([alpha](D)) of the homopolymer were -69.7 to -65.9 degrees. Radical copolymerizations of CHPAM (M(1)) were performed with styrene (ST, M(2)) or methyl methacrylate (MMA, M(2)) in benzene at 60 degrees C. The monomer reactivity ratios (r(1), r(2)) and Alfrey-Price Q-e were determined as follows: r(1) = 0.27, r(2) = 0.11, Q(1) = 2.00, e(1) = 1.07 in the CHPAM-ST system; r(1) = 0.07, r(2) = 3.22, Q(1) = 0.38, e(1) = 1.63 in the CHPAM-MMA system. Circular dichroism (CD) spectra of the copolymers remarkably varied with increasing content of CHPAM, Relationships between [alpha](D) and content (wt%) of CHPAM in the copolymer showed significant deviation from linearity. This suggests that asymmetric perturbation of the side chain chromophore and asymmetric induction in M(1)-M(2) unit of the copolymer may occur.