Useful synthetic method of polypeptides with well‐defined structure by polymerization of activated urethane derivatives of α‐amino acids

A facile polymerization strategy for synthesis of polypeptides with well-defined structure using urethane derivatives of α-amino acids in the presence of amine is reported. N-(phenoxycarbonyl) α-amino acid was polymerized at 60°C in N,N-dimethyl acetamide (DMAc). The obtained polypeptides were adjusted by varying the initial ratio of urethane derivatives to amine, and the molecular weight distribution remained narrow (below 1.35). MALDI-TOF-MS revealed that the obtained polypeptides had amine-incorporated initiating end and amino group at propagating end without any side reactions, terminating chain growth. The block copolypeptides were established by polymerization of urethane derivatives in the presence of amine, followed by subsequent addition of other urethane derivatives.