Syntheses of potent, selective, and orally bioavailable indazole-pyridine series of protein kinase B/Akt inhibitors with reduced hypotension

J Med Chem. 2007 Jun 28;50(13):2990-3003. doi: 10.1021/jm0701019. Epub 2007 May 25.

Abstract

Compound 7 was identified as a potent (IC50 = 14 nM), selective, and orally bioavailable (F = 70% in mouse) inhibitor of protein kinase B/Akt. While promising efficacy was observed in vivo, this compound showed effects on depolarization of Purkinje fibers in an in vitro assay and CV hypotension in vivo. Guided by an X-ray structure of 7 bound to protein kinase A, which has 80% homology with Akt in the kinase domain, our efforts have focused on structure-activity relationship (SAR) studies of the phenyl moiety, in an attempt to address the cardiovascular liability and further improve the Akt potency. A novel and efficient synthetic route toward diversely substituted phenyl derivatives of 7 was developed utilizing a copper-mediated aziridine ring-opening reaction as the key step. To improve the selectivity of these Akt inhibitors over other protein kinases, a nitrogen atom was incorporated into selected phenyl analogues of 7 at the C-6 position of the methyl indazole scaffold. These modifications resulted in the discovery of inhibitor 37c with greater potency (IC50 = 0.6 nM vs Akt), selectivity, and improved cardiovascular safety profile. The SARs, pharmacokinetic profile, and CV safety of selected Akt inhibitors will be discussed.

MeSH terms

  • Administration, Oral
  • Animals
  • Biological Availability
  • Crystallography, X-Ray
  • Dogs
  • Hypotension / chemically induced*
  • Indazoles / adverse effects
  • Indazoles / chemical synthesis*
  • Indazoles / pharmacology
  • Mice
  • Models, Molecular
  • Protein Conformation
  • Proto-Oncogene Proteins c-akt / antagonists & inhibitors*
  • Purkinje Fibers / drug effects
  • Purkinje Fibers / physiology
  • Pyrazoles / adverse effects
  • Pyrazoles / chemical synthesis*
  • Pyrazoles / pharmacology
  • Pyridines / adverse effects
  • Pyridines / chemical synthesis*
  • Pyridines / pharmacology
  • Rats
  • Stereoisomerism
  • Structure-Activity Relationship

Substances

  • 1-(5-(3-methyl-1H-pyrazolo(3,4-c)pyridin-5-yl)pyridin-3-yloxy)-3-(3-(trifluoromethyl)phenyl)propan-2-amine
  • Indazoles
  • Pyrazoles
  • Pyridines
  • Proto-Oncogene Proteins c-akt