Synthesis of novel chiral poly(methacrylate)s having urea moieties and (S)-methylbenzyl or L-phenylalanine methyl ester groups and their chiral recognition abilities

Abstract

New chiral methacrylates, (S)-methylbenzyl methacryloyloxyethyl urea (MBMOU) and (S)-methoxycarbonylbenzylmethyl methacryloyloxyethyl urea (MCMOU) were synthesized from 2-(methacryloyloxy)ethyl isocyanate (MOI) and (S)-methylbenzylamine and L-phenylalanine methyl ester, respectively. Radical polymerizations of MBMOU and MCMOU were performed under several conditions to obtain the corresponding polymers whose specific optical rotations ([α]43525) were - 13.5° to - 10.9° and 30.8° to 31.5°, respectively. From the result radical copolymerizations of RMOU (MBMOU and MCMOU, M1) with styrene (ST, M2) or butyl methacrylate (BMA, M2), monomer reactivity ratios (r1, r2) and Alfrey-Price Q-e were determined. The chiroptical properties of poly(MBMOU-co-M2)s were strongly influenced by co-units. Poly(RMOU)-bonded-silica gel as chiral stationary phase (CSP) was prepared for high performance liquid chromatography (HPLC). The CSPs resolved some racemates such as ketoprofen and ethyl mandelate. The enantiorecognition ability may be based on higher-ordered structures of the polymer.