The mixed azines 4 and 5 were prepared by reaction of naloxazone (2) w
ith either oxymorphone (6) or 14-O-methyloxymorphone (7) and tested in
vitro using opioid receptor binding assays and in vivo using the AcOH
-writhing test in mice. Compound 4 was found to be a partial agonist,
while compound 5 was a potent opioid agonist with higher potency than
morphine.