Synthesis of boronophenylalanine-like aza-amino acids for boron-containing azapeptide precursors

Abstract

Aza-amino acids and an azapeptide with a boron-containing substituent were developed for the first time. We synthesized p-boronophenylalanine (BPA)-like aza-amino acid (aza-BPA) and its analogs in which the α-carbon of the peptide is replaced by nitrogen and the boronate ester is situated at the ortho, meta, or para position of the phenyl group. The N- and C-terminals of aza-BPA were linked to α-amino acids to afford an α/aza/α-tripeptide. These compounds are expected to be used in boron neutron capture therapy, chemotherapy, and synthesis of functional materials.