Discovery and SAR Evolution of Pyrazole Azabicyclo[3.2.1]octane Sulfonamides as a Novel Class of Non-Covalent N-Acylethanolamine-Hydrolyzing Acid Amidase (NAAA) Inhibitors for Oral Administration

J Med Chem. 2021 Sep 23;64(18):13327-13355. doi: 10.1021/acs.jmedchem.1c00575. Epub 2021 Sep 1.

Abstract

Inhibition of intracellular N-acylethanolamine-hydrolyzing acid amidase (NAAA) activity is a promising approach to manage the inflammatory response under disabling conditions. In fact, NAAA inhibition preserves endogenous palmitoylethanolamide (PEA) from degradation, thus increasing and prolonging its anti-inflammatory and analgesic efficacy at the inflamed site. In the present work, we report the identification of a potent, systemically available, novel class of NAAA inhibitors, featuring a pyrazole azabicyclo[3.2.1]octane structural core. After an initial screening campaign, a careful structure-activity relationship study led to the discovery of endo-ethoxymethyl-pyrazinyloxy-8-azabicyclo[3.2.1]octane-pyrazole sulfonamide 50 (ARN19689), which was found to inhibit human NAAA in the low nanomolar range (IC50 = 0.042 μM) with a non-covalent mechanism of action. In light of its favorable biochemical, in vitro and in vivo drug-like profile, sulfonamide 50 could be regarded as a promising pharmacological tool to be further investigated in the field of inflammatory conditions.

MeSH terms

  • Amidohydrolases / antagonists & inhibitors*
  • Amidohydrolases / metabolism
  • Animals
  • Anti-Inflammatory Agents / chemical synthesis
  • Anti-Inflammatory Agents / metabolism
  • Anti-Inflammatory Agents / pharmacokinetics
  • Anti-Inflammatory Agents / pharmacology*
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / metabolism
  • Enzyme Inhibitors / pharmacokinetics
  • Enzyme Inhibitors / pharmacology*
  • Humans
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Microsomes, Liver / metabolism
  • Molecular Docking Simulation
  • Molecular Structure
  • Protein Binding
  • Pyrazoles / chemical synthesis
  • Pyrazoles / metabolism
  • Pyrazoles / pharmacokinetics
  • Pyrazoles / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Structure-Activity Relationship
  • Tropanes / chemical synthesis
  • Tropanes / metabolism
  • Tropanes / pharmacokinetics
  • Tropanes / pharmacology*

Substances

  • Anti-Inflammatory Agents
  • Enzyme Inhibitors
  • Pyrazoles
  • Tropanes
  • Amidohydrolases
  • N-acylethanolamine-hydrolyzing acid amidase, rat
  • NAAA protein, human