Azapeptides -A History of Synthetic Milestones and Key Examples.

For over 50 years of azapeptide synthetic techniques, developments have renewed the field of peptidomimetic therapeutics. Azapeptides are close surrogates of natural peptides: they contain a substitution of the amino acid α-carbon by a nitrogen atom. Goserelin (1989) and Atazanavir (2003) are two well-known, FDA-approved azapeptide-based drugs for the treatment of cancers and HIV infection, providing evidence for the successful clinical implementation of this class of therapeutic. This review highlights the azapeptides in recent medicinal chemistry applications and synthetic milestones. We describe the current techniques for azapeptide bond formation by introducing azapeptide coupling reagents and chain elongation methods both in solution and solid-phase strategies.