New polyurethanes derived from amino acids: Synthesis and characterization of α,ω-diaminooligopeptides by ring-opening polymerization of glutamate N-carboxyanhydrides

Strictly aminotelechelic oligopeptides with γ-methylglutamate or γ-benzylglutamate units were synthesized by oligomerization of the corresponding N-carboxyanhydride initiated by ethylenediamine. The degree of polymerization (DP) was controlled by the ratio of NCA to ethylenediamine concentrations for reaction times of less than 1 h and DP=20. The aminotelechelic nature, which greatly depends on the conditions used during oligomerization, was confirmed by amino end-group quantification. Characterization was achieved by 1H and 13C NMR and IR spectroscopy.