Cyclic RGD peptides containing azabicycloalkane reverse-turn mimics

The Fmoc-protected lactams 3 and 4 were used to prepare cyclo(Arg-Gly-Asp-lactam) 1 and cyclo(Arg-Gly-Asp-Phe-lactam) 2, which contain the Arg-Gly-Asp (RGD) recognition motif. Their solid-phase synthesis, conformational analysis, and binding to purified alpha(v)beta(3) and alpha(v)beta(5) integrins are reported. Compound 1 was found to act as an active and selective inhibitor of the alpha(v)beta(5) integrin.