Facile synthesis of N-phenoxycarbonyl amino acids by a two-phase reaction for direct polymerization

Polypeptides are extensively used in the fields of biomedicine and biomaterials. The use of N-phenoxycarbonyl amino acids (NPCs) as monomers for polypeptide synthesis is an advanced method that offers the unique advantage of excellent monomer stability. However, the purification of NPC monomers previously required laborious column chromatography or recrystallization techniques, which might have restricted the widespread application of NPC polymerization. In this work, a straightforward and efficient method for synthesizing NPC monomers has been developed, enabling the production of products with high purity through a simple work-up process. This method is compatible with various amino acids, and the resulting monomers can undergo normal polymerization reactions. By significantly enhancing the availability of NPC monomers, this method facilitates the synthesis of polypeptides.