Discovery and optimization of a novel series of N-arylamide oxadiazoles as potent, highly selective and orally bioavailable cannabinoid receptor 2 (CB2) agonists

J Med Chem. 2008 Aug 28;51(16):5019-34. doi: 10.1021/jm800463f. Epub 2008 Aug 5.

Abstract

The CB2 receptor is an attractive therapeutic target for analgesic and anti-inflammatory agents. Herein we describe the discovery of a novel class of oxadiazole derivatives from which potent and selective CB2 agonist leads were developed. Initial hit 7 was identified from a cannabinoid target-biased library generated by virtual screening of sample collections using a pharmacophore model in combination with a series of physicochemical filters. 7 was demonstrated to be a selective CB2 agonist (CB2 EC50 = 93 nM, Emax = 98%, CB1 EC50 > 10 microM). However, this compound exhibited poor solubility and relatively high clearance in rat, resulting in low oral bioavailability. In this paper, we report detailed SAR studies on 7 en route toward improving potency, physicochemical properties, and solubility. This effort resulted in identification of 63 that is a potent and selective agonist at CB2 (EC50 = 2 nM, Emax = 110%) with excellent pharmacokinetic properties.

MeSH terms

  • Administration, Oral
  • Aminoquinolines / administration & dosage
  • Aminoquinolines / chemical synthesis*
  • Aminoquinolines / pharmacokinetics
  • Animals
  • Biological Availability
  • CHO Cells
  • Cricetinae
  • Cricetulus
  • Drug Evaluation, Preclinical
  • Humans
  • Models, Molecular
  • Oxadiazoles / administration & dosage
  • Oxadiazoles / chemical synthesis*
  • Oxadiazoles / pharmacokinetics
  • Rats
  • Receptor, Cannabinoid, CB2 / agonists*
  • Structure-Activity Relationship

Substances

  • 6-chloro-N-(3-(3-(2-chloro-4-fluorophenyl)-1,2,4-oxadiazol-5-yl)propyl)quinolin-3-amine
  • Aminoquinolines
  • Oxadiazoles
  • Receptor, Cannabinoid, CB2