Redefining the Structure−Activity Relationships of 2,6-Methano-3-benzazocines. 4. Opioid Receptor Binding Properties of 8-[<i>N</i>-(4‘-phenyl)-phenethyl)carboxamido] Analogues of Cyclazocine and Ethylketocycalzocine

The synthesis and evaluation of a series of aryl-containing N-monosubstituted analogues of the lead compound 8-carboxamidocyclazocine were performed to probe a putative hydrophobic binding pocket of opioid receptors. High binding affinity to μ, κ, and δ opioid receptors was observed for the 8-[N-(4‘-phenyl)-phenethyl)carboxamido] analogue