Studies on peptides. CXXXI. Synthesis of adrenorphin and enkephalin analogs.

Abstract
Adrenorphin, H-Tyr-Gly-Gly-Phe-Met-Arg-Arg-Val-NH2, and its D-Met (O)2-analog were synthesized. In addition, analogs of [Arg6, Phe7] enkephalin substituted at the 2nd position by D-Ala and D-Met (O) were also synthesized, together with four other enkephalin analogs. Among these compounds, [D-Met (O)2] adrenorphin exhibited high analgesic activity (29.1 times that of morphine) antagonized by naloxone, when administered intracisternally to mice.