Analogues of the opioid peptides [D-Phe(3)]morphiceptin (H-Tyr-Pro-D-Phe-Pro-NH2) and endomorphin-2 (H-Tyr-Pro-Phe-Phe-NH2) containing the pseudoproline (Psi Pro) (4R)-thiazolidine-4-carboxylic acid (CyS[Psi (R1,R2) pro]) or (4S)-oxazolidine-4-carboxylic a ...
2001