Design and Synthesis of Benzimidazoles As Novel Corticotropin-Releasing Factor 1 Receptor Antagonists

J Med Chem. 2016 Mar 24;59(6):2551-66. doi: 10.1021/acs.jmedchem.5b01715. Epub 2016 Mar 7.


Benzazole derivatives with a flexible aryl group bonded through a one-atom linker as a new scaffold for a corticotropin-releasing factor 1 (CRF1) receptor antagonist were designed, synthesized, and evaluated. We expected that structural diversity could be expanded beyond that of reported CRF1 receptor antagonists. In a structure-activity relationship study, 4-chloro-N(2)-(4-chloro-2-methoxy-6-methylphenyl)-1-methyl-N(7),N(7)-dipropyl-1H-benzimidazole-2,7-diamine 29g had the most potent binding activity against a human CRF1 receptor and the antagonistic activity (IC50 = 9.5 and 88 nM, respectively) without concerns regarding cytotoxicity at 30 μM. Potent CRF1 receptor-binding activity in brain in an ex vivo test and suppression of stress-induced activation of the hypothalamus-pituitary-adrenocortical (HPA) axis were also observed at 138 μmol/kg of compound 29g after oral administration in mice. Thus, the newly designed benzimidazole 29g showed in vivo CRF1 receptor antagonistic activity and good brain penetration, indicating that it is a promising lead for CRF1 receptor antagonist drug discovery research.

MeSH terms

  • Adrenocorticotropic Hormone / metabolism
  • Animals
  • Benzimidazoles / antagonists & inhibitors*
  • Benzimidazoles / pharmacology*
  • Brain Chemistry / drug effects
  • CHO Cells
  • Cricetinae
  • Cricetulus
  • Drug Design
  • Humans
  • Hypothalamo-Hypophyseal System / drug effects
  • Mice
  • Models, Molecular
  • Pituitary-Adrenal System / drug effects
  • Receptors, Corticotropin-Releasing Hormone / antagonists & inhibitors*
  • Structure-Activity Relationship


  • Benzimidazoles
  • Receptors, Corticotropin-Releasing Hormone
  • CRF receptor type 1
  • Adrenocorticotropic Hormone