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

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.