14-amino, 14-alkylamino, and 14-acylamino analogs of oxymorphindole. Differential effects on opioid receptor binding and functional profiles

The 14-amino analogue of oxymorphindole (OMI) was synthesized and found to possess delta-opioid binding affinity and selectivity similar to OMI. Substitution of the amino group with alkyl, arylalkyl, and acyl groups had relatively little effect on delta-affinity but delta-selectivity was reduced. In functional assays the 14-phenylacetylamino derivative 6d was a selective delta-agonist whereas the phenethylamino analogue 5d was a mu-agonist and low efficacy delta partial agonist that warrants further investigation as an analgesic with low tolerance and dependence.