Macrocyclic diketopiperazine receptors: effect of macrocyclization on the binding properties of two-armed receptors

The synthesis of macrocyclic two-armed diketopiperazine receptors and their binding properties toward peptides is described. Macrocyclization with short linkers led to receptors with significantly modified binding properties compared to their flexible open chain parent receptors, whereas with long linkers the original binding selectivities were largely retained.