Helical polymer carrying helical grafts from peptide-based acetylene macromonomers: Synthesis

N-Propargylamide-terminated peptide-based macromonomers with a degree of polymerization ranging from 4 to 40 were synthesized by the polymerization of gamma-benzyl and gamma-stearyl-L-glutamate-N-carboxy anhydrides initiated with propargylamine. The macromonomers took an a-helical structure, which was confirmed by signals at 208 and 220 nm in CD spectra. The macromonomers were subjected to polymerization and copolymerization with an alanine-derived N-propargylamide [N-(tert-butoxycarbonyl)L-alanine-N'-propargylamide] catalyzed with (2,5-norbornadiene)-Rh+[eta(6-)C(6)H(5)B(-)(C6H5)(3)]. It was confirmed through a CD spectroscopic study that the copolymer obtained from the copolymerization of the T-stearyl-L-glutamate-based macromonomer with the alanine-derived N-propargylamide had a helical polyacetylene main chain and helical polypeptide side chains.