Identification of imidazo-pyrrolopyridines as novel and potent JAK1 inhibitors

J Med Chem. 2012 Jun 28;55(12):5901-21. doi: 10.1021/jm300438j. Epub 2012 Jun 11.

Abstract

A therapeutic rationale is proposed for the treatment of inflammatory diseases, such as rheumatoid arthritis (RA), by specific targeting of the JAK1 pathway. Examination of the preferred binding conformation of clinically effective, pan-JAK inhibitor 1 led to identification of a novel, tricyclic hinge binding scaffold 3. Exploration of SAR through a series of cycloamino and cycloalkylamino analogues demonstrated this template to be highly tolerant of substitution, with a predisposition to moderate selectivity for the JAK1 isoform over JAK2. This study culminated in the identification of subnanomolar JAK1 inhibitors such as 22 and 49, having excellent cell potency, good rat pharmacokinetic characteristics, and excellent kinase selectivity. Determination of the binding modes of the series in JAK1 and JAK2 by X-ray crystallography supported the design of analogues to enhance affinity and selectivity.

MeSH terms

  • Animals
  • Cell Line
  • Imidazoles / chemistry*
  • Janus Kinase 1 / antagonists & inhibitors*
  • Janus Kinase 1 / chemistry
  • Janus Kinase 2 / antagonists & inhibitors
  • Janus Kinase 2 / chemistry
  • Models, Molecular
  • Protein Kinase Inhibitors / chemical synthesis
  • Protein Kinase Inhibitors / chemistry*
  • Protein Kinase Inhibitors / pharmacokinetics
  • Protein Kinase Inhibitors / pharmacology*
  • Protein Structure, Tertiary
  • Pyridines / chemical synthesis
  • Pyridines / chemistry*
  • Pyridines / pharmacokinetics
  • Pyridines / pharmacology*
  • Rats
  • Substrate Specificity

Substances

  • Imidazoles
  • Protein Kinase Inhibitors
  • Pyridines
  • imidazole
  • Janus Kinase 1
  • Janus Kinase 2