Synthesis and biological evaluation of 14-alkoxymorphinans.12.1 A phenethyl analogue of the μ-selective opioid receptor antagonist cyprodime

Abstract The N -phenethyl analogue (compound 4 ) of the μ-selective opioid antagonist cyprodime ( 1 ) has been prepared and evaluated in radioligand binding, bioassays (guinea-pig ileum myenteric plexus and mouse vas deferens preparations) and the rat tail flick test. It was found to possess remarkable affinity and high preference for μ opioid receptors and high antinociceptive potency which is comparable to its N -methyl analogue 3 .