Azadepsipeptides: synthesis and evaluation of a novel class of peptidomimetics.

A general route to azadepsipeptides, a new class of pseudopeptides, has been established. The methodology was applied to the synthesis of a bis-aza analogue of the antiparasitic cyclooctadepsipeptide PF1022A. Comparison of the X-ray crystal structures of natural PF1022A (8) and the chimeric aza analogue 9 revealed that the introduction of nitrogen in the backbone of PF1022A results in almost complete conservation of the 3D structure with only minor deviations at the new nitrogen positions.