Synthesis and conformation of poly(L-gamma-chloroethyl glutamate)

Triphosgene was used to react with gamma-chloroethyl glutamate, which was s ynthesized from 2-ethylene chlorohydrin and L-glutamic acid, to give gamma- chloroethyl glutamate N-carboxyanhydride (NCA). Thus, poly(gamma-chloroethy l glutamate), a new poly(amino acid) with reactive chloride, was obtained f rom the NCA by using triertlylamine as the initiator which can lead to intr insic viscosity of polypeptide, [eta], over 50 mL/g. NCA and polymer were c haracterized by IR, H-1 NMR and C-13 NMR. Oligomer of gamma-chloroethyl glu tamate was also obtained while NCA was initiated by moisture in air. The co nformations of oligomer and polymer of gamma-chloroethyl glutamate were obs erved by IR and CD spectroscopy. The results suggested that the conformatio n of oligomer mainly be beta-sheet, while the polymer be alpha-helix.