Potent Integrin Antagonists from a Small Library of RGD-Including Cyclic Pseudopeptides

A small library of cyclic RGD pseudopentapeptides incorporating stereoisomeric 6,5- and 7,5-fused bicyclic lactams was synthesized with the aim of developing active and selective integrin antagonists. The solid-phase synthesis and activity of these RGD derivatives is described. The approach led to two of the most active known inhibitors of alphavbeta3 receptor.