Design, Synthesis, and Evaluation of Opioid Analogues with Non-Peptidic β-Turn Scaffold: Enkephalin and Endomorphin Mimetics

We have identified a mu-selective opioid receptor agonist without a cationic amino group in the molecule from libraries of bicyclic beta-turn peptidomimetics. The biologically active conformation of the lead is proposed to mimic an endomorphin type III 4 --1 beta-turn conformation.