Variation of the aryl substituent on the piperazine ring within the 4-(piperazin-1-yl)-2,6-di(pyrrolidin-1-yl)pyrimidine scaffold unveils potent, non-competitive inhibitors of the inflammatory caspases

Bioorg Med Chem Lett. 2016 Nov 15;26(22):5476-5480. doi: 10.1016/j.bmcl.2016.10.025. Epub 2016 Oct 12.

Abstract

The inflammatory caspases (caspase-1, -4 and -5) are potential therapeutic targets for autoimmune and inflammatory diseases due to their involvement in the immune response upon inflammasome formation. A series of small molecules based on the 4-(piperazin-1-yl)-2,6-di(pyrrolidin-1-yl)pyrimidine scaffold were synthesized with varying substituents on the piperazine ring. Several compounds were pan-selective inhibitors of the inflammatory caspases, caspase-1, -4 and -5, with the ethylbenzene derivative CK-1-41 displaying low nanomolar Ki values across this family of caspases. Three analogs were nearly 10 fold selective for caspase-5 over caspase-1 and -4. The compounds display non-competitive, time dependent inhibition profiles. To our knowledge, this series is the first example of small molecule inhibitors of all three inflammatory caspases.

Keywords: Caspase-1; Caspase-4; Caspase-5; Inflammasome; Inflammation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caspase 1 / chemistry
  • Caspase 1 / metabolism*
  • Caspase Inhibitors / chemistry*
  • Caspase Inhibitors / pharmacology*
  • Caspases / chemistry
  • Caspases / metabolism*
  • Caspases, Initiator / chemistry
  • Caspases, Initiator / metabolism*
  • Humans
  • Inflammation / drug therapy
  • Inflammation / enzymology
  • Molecular Docking Simulation
  • Piperazines / chemistry*
  • Piperazines / pharmacology*
  • Pyrimidines / chemistry
  • Pyrimidines / pharmacology
  • Small Molecule Libraries / chemistry
  • Small Molecule Libraries / pharmacology

Substances

  • Caspase Inhibitors
  • Piperazines
  • Pyrimidines
  • Small Molecule Libraries
  • CASP4 protein, human
  • CASP5 protein, human
  • Caspases
  • Caspases, Initiator
  • Caspase 1