Optically active polymethacrylamides bearing a bulky oxazoline pendant: Synthesis and characterization

A novel type of chiral methacrylamide derivatives, N-[o-(4-phenyl-4,5-dihydro-1,3-oxazol-2-yl)phenyl]methacrylamide ((R)-PhOPMAM), N-[o-(4-isopropyl-4,5-dihydro-1,3-oxazol-2-yl)phenyl]methacrylamide ((S)-PriOPMAM), and N-[o-(4-isopropyl-4,5-dihydro-1,3-oxazol-2-yl)phenyl]methacrylamide ((S)-MeOPMAM), was synthesized and radically polymerized to the corresponding polymers in moderate yields. The polymerization characteristics and the chiroptical behavior of the resultant polymers have been examined in detail by using circular dichroism (CD), UV-Vis, and NMR spectroscopies in comparison with our previous observation. It was found that the oxazoline moieties have an effective influence on both the polymerization process and the optical activity of obtained polymers. Especially, the levorotatory monomer (S)-MeOPMAM ([α]D25=-7.7°) was transformed to the polymers with dextrorotation activity ([α]D25=+102.0°to+117.1°), indicating the polymer main chain might exist a helical conformation. Also, the chiral recognition ability was briefly evaluated by 1H NMR technique for the poly(OPMAM)s.