3‐[3‐(Phenalkylamino)cyclohexyl]phenols: Synthesis, biological activity, and in silico investigation of a naltrexone‐derived novel class of MOR‐antagonists

Abstract

The development of novel μ-opioid receptor (MOR) antagonists is one of the main objectives of drug discovery and development. Based on a simplified version of the morphinan scaffold, 3-[3-(phenalkylamino)cyclohexyl]phenol analogs were designed, synthesized, and evaluated for their MOR antagonist activity in vitro and in silico. At the highest concentrations, the compounds decreased by 52% to 75% DAMGOinduced GTPγS stimulation, suggesting that they acted as antagonists. Moreover, Extra-Precision Glide and Generalized-Born Surface Area experiments provided useful information on the nature of the ligand-receptor interactions, indicating a peculiar combination of C-1 stereochemistry and N-substitutions as feasibly essential for MOR-ligand complex stability. Interestingly, compound 9 showed the best experimental binding affinity, the highest antagonist activity, and the finest MOR-ligand complex stability. In silico experiments also revealed that the most promising stereoisomer (1R, 3R, 5S) 9 retained 1,3-cis configuration with phenol ring equatorial oriented. Further studies are needed to better characterize the pharmacodynamics and pharmacokinetic properties of these compounds.[ 3 H]DAMGO binding assay, 3-[3-(phenalkylamino)cyclohexyl]phenols, GTPγS assay, in silico study, MOR antagonists 1 | INTRODUCTION Despite the serious and potentially fatal adverse effects, μ-opioid receptor (MOR) agonists such as morphine, oxycodone, and fentanyl, have been over/misprescribed in recent years, resulting in a dramatic increase in opioid dependence, illegal opioid use, and opioid-related deaths. Opioid antagonists are a class of drugs that bind competitively to one or more of the opioid receptors, present little or no intrinsic activity, and robustly antagonize the effects of receptor agonists. They are utilized as antidotes for opioid overdose (naloxone) and approved for the treatment of opioid and alcohol dependence (naltrexone). Several structural classes have been identified as MOR antagonists with variable

In silico characterization of ligand–receptor interactions for U‐47700, N,N‐didesmethyl‐U‐47700, U‐50488 at mu‐ and kappa‐opioid receptors

“…The following protocol was used to prepare the simulated systems. [35][36][37] The MOR and KOR models were built from the crystallographic structures of M. musculus MOR (PDB ID 6DDF) [23] and H. sapiens KOR (PDB ID 6VI4) coupled to their G-proteins. [24] The MOR and KOR were crystallized in the active state with the agonist [D-Ala 2 , N-MePhe 4 , Glyol]-enkephalin (for MOR) or the agonist (3R)-7-hydroxy-N-{(2S)-1-[(3R,4R)-4-(3-hydroxyphenyl)-3,4-dimethylpiperidin-1-yl]-3-methylbutan-2-yl}-1,2,3,4-tetrahydroisoquinoline-3-carboxamide (for KOR) occupying the binding site.…”