Synthesis and Pharmacological Evaluation of 1,2-Dihydrospiro[isoquinoline-4(3<i>H</i>),4′-piperidin]-3-ones as Nociceptin Receptor Agonists

Abstract

Some synthesized 1,2-dihydrospiro[isoquinoline-4(3 H),4'-piperidin]-3-ones were evaluated as ligands for nociceptin receptor (NOP receptor). Their affinity was established by binding studies, and efficacy was investigated by GTP binding experiments. Selectivity toward DOP, KOP, and MOP receptors was assessed, and structural requirements affecting affinity and selectivity were remarked. Most notably, compound 6d displayed nanomolar NOP receptor affinity and showed more than 800-fold selectivity. The new structures exerted full or partial agonistic activity.