Synthesis of Boronophenylalanine-Like Aza-Amino Acids for Boron-Containing Azapeptide Precursors

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 alpha-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 alpha-amino acids to afford an alpha/aza/alpha-tripeptide. These compounds are expected to be used in boron neutron capture therapy, chemotherapy, and synthesis of functional materials. (C) 2020 Elsevier Ltd. All rights reserved.