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 αvβ3 and αvβ5 integrins are reported. Compound 1 was found to act as an active and selective inhibitor of the αvβ5 integrin.