Syntheses and Radical Polymerization Behavior of Methacrylamides Having Peptide Moieties: Effect of the Methylene Chain Introduced between the Methacrylamide and Peptide Moieties on the Polymerizability and Polymer Structure

Syntheses and radical polymerization behavior of methacrylamides having peptide moieties, N -(methacryloylglycyl)- l -leucyl- l -alanine methyl ester (MA-GLA-M) and N -(methacryloyl-β-alanyl)- l -leucyl- l -alanine methyl ester (MA-βLA-M), were examined. Radical polymerizations of MA-GLA-M and MA-βLA-M in the presence of AIBN (1 mol %) in DMF (1.0 mol/L) afforded the corresponding polymers (poly(MA-GLA-M) and poly(MA-βLA-M)) in nearly quantitative conversions with 68 000 and 69 000, respectively. An increase of the absolute value of molecular rotation on the transformation from MA-GLA-M (−126.0°) and MA-βLA-M (−132.9°) to poly(MA-GLA-M) (−176.5°) and poly(MA-βLA-M) (−242.1°) could be observed. The radical polymerizability of MA-βLA-M in MeOH was suggested to be lower than that of MA-GLA-M. The CD patterns of poly(MA-GLA-M) and poly(MA-βLA-M) were similar to those of the corresponding model compounds.