Synthesis and pharmacological activity of dermorphin and its N-terminal sequences

H-Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH₂ (demorphin), an opiate-like peptide, and tri-, tetra-, penta- and hexapeptide-amide analogs, were synthesized by conventional methods in solution, to determine the minimum peptide chain-length, required for analgesic activity.