Syntheses and Polymerizations of Novel Chiral Methacrylates Bearing Urethane Bonds and N,N-Dibenzylamino Groups

Abstract

Four new chiral methacrylates bearing urethane bonds and N,N-dibenzylamino groups (RMOC) were synthesized from 2-methacryloyloxyethyl isocyanate (MOI) and four chiral alcohol derivatives of α-amino acids, L-valine, L-leucine, D-phenylglycine, and L-phenylalanine. Radical polymerizations of RMOC were performed under various conditions to obtain the corresponding poly(RMOC) with number average molecular weights (M̅n) of 2.4×104—6.4×104. Poly(RMOC) has hydrogen bonds based on urethane segments in solvent and exhibited negative (levo) rotation. Specific optical rotations of poly(RMOC) were slightly influenced by solvent and temperature. Radical copolymerizations of RMOC with styrene (ST) and methyl methacrylate (MMA) were performed with AIBN in toluene at 60°C. Monomer reactivity ratios (r1, r2) and Alfrey-Price Q-e were determined. Chiroptical properties of the copolymers were scarcely affected by co-units of ST and MMA. Chiral stationary phases (CSPs) for high performance liquid chromatography (HPLC) were prepared from poly(RMOC) and silica gel and optical resolution ability was investigated. CSPs resolved some racemic compounds (1—5) using methanol/water as mobile phase.