Discovery of N-(1-ethylpropyl)-[3-methoxy-5-(2-methoxy-4-trifluoromethoxyphenyl)-6-methyl-pyrazin-2-yl]amine 59 (NGD 98-2): an orally active corticotropin releasing factor-1 (CRF-1) receptor antagonist

J Med Chem. 2011 Jun 23;54(12):4187-206. doi: 10.1021/jm200365y. Epub 2011 May 27.

Abstract

The design, synthesis, and structure-activity relationships of a novel series of pyrazines, acting as corticotropin releasing factor-1 (CRF-1) receptor antagonists, are described. Synthetic methodologies were developed to prepare a number of substituted pyrazine cores utilizing regioselective halogenation and chemoselective derivatization. Noteworthy, an efficient 5-step synthesis was developed for the lead compound 59 (NGD 98-2), which required no chromatography. Compound 59 was characterized as an orally bioavailable, brain penetrant, and highly selective CRF-1 receptor antagonist. Occupancy of rat brain CRF-1 receptors was quantified using ex vivo receptor occupancy assays, using both brain tissue homogenates as well as brain slices receptor autoradiography. Behaviorally, oral administration of 59 significantly antagonized CRF-induced locomotor activity at doses as low as 10 mg/kg and dose-dependently reduced the restraint stress-induced ACTH increases.

MeSH terms

  • Adipose Tissue / metabolism
  • Administration, Oral
  • Adrenocorticotropic Hormone / blood
  • Animals
  • Biological Availability
  • Blood-Brain Barrier / metabolism
  • Cell Line
  • Cerebral Cortex / metabolism
  • Humans
  • In Vitro Techniques
  • Injections, Intraventricular
  • Male
  • Microsomes, Liver / metabolism
  • Motor Activity / drug effects
  • Pyrazines / chemical synthesis*
  • Pyrazines / chemistry
  • Pyrazines / pharmacology
  • Radioligand Assay
  • Rats
  • Receptors, Corticotropin-Releasing Hormone / antagonists & inhibitors*
  • Receptors, Corticotropin-Releasing Hormone / metabolism
  • Restraint, Physical
  • Structure-Activity Relationship

Substances

  • N-(1-ethylpropyl)-(3-methoxy-5-(2-methoxy-4-trifluoromethoxyphenyl)-6-methyl-pyrazin-2-yl)amine
  • Pyrazines
  • Receptors, Corticotropin-Releasing Hormone
  • CRF receptor type 1
  • Adrenocorticotropic Hormone