Oxyazapeptides: Synthesis, Structure Determination, and Conformational Analysis

Herein we report the synthesis, X-ray structure determination, and conformational analysis of a novel class of heteroatom-modified peptidomimetics, which we shall call “oxyazapeptides”. Substituting the typical native N-Cα bond with an O-Nα bond creates a completely new, previously unknown family of peptidomimetics, which are hydrolytically stable and display very interesting conformational behavior. Force field calculations revealed that the barrier to rotation around the O-Nα bond in oxyazapeptides is five times lower than that around the N-Nα bond in azapeptides. Also, conformational analysis supported by X-ray suggests that the oxyaza moiety can effectively induce β-turns, which can make the newly discovered oxyazapeptide scaffold a useful tool for drug discovery and for design of biologics.