Application of tri- and tetrasubstituted alkene dipeptide mimetics to conformational studies of cyclic RGD peptides

ψ[(E)-CMeCH]- and ψ[(E)-CMeCMe]-type alkene isosteres are potential -CO-NH- and -CO-NMe-type peptide bond mimetics, respectively. The application of these chiral isosteres to conformational studies on cyclic RGD peptides having potent integrin antagonistic activities is reported.