Achiral pyrazinone-based inhibitors of the hepatitis C virus NS3 protease and drug-resistant variants with elongated substituents directed toward the S2 pocket

J Med Chem. 2014 Mar 13;57(5):1790-801. doi: 10.1021/jm301887f. Epub 2013 Apr 2.

Abstract

Herein we describe the design, synthesis, inhibitory potency, and pharmacokinetic properties of a novel class of achiral peptidomimetic HCV NS3 protease inhibitors. The compounds are based on a dipeptidomimetic pyrazinone glycine P3P2 building block in combination with an aromatic acyl sulfonamide in the P1P1' position. Structure-activity relationship data and molecular modeling support occupancy of the S2 pocket from elongated R(6) substituents on the 2(1H)-pyrazinone core and several inhibitors with improved inhibitory potency down to Ki = 0.11 μM were identified. A major goal with the design was to produce inhibitors structurally dissimilar to the di- and tripeptide-based HCV protease inhibitors in advanced stages of development for which cross-resistance might be an issue. Therefore, the retained and improved inhibitory potency against the drug-resistant variants A156T, D168V, and R155K further strengthen the potential of this class of inhibitors. A number of the inhibitors were tested in in vitro preclinical profiling assays to evaluate their apparent pharmacokinetic properties. The various R(6) substituents were found to have a major influence on solubility, metabolic stability, and cell permeability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Hepacivirus / drug effects
  • Hepacivirus / enzymology
  • Magnetic Resonance Spectroscopy
  • Protease Inhibitors / chemistry
  • Protease Inhibitors / metabolism
  • Protease Inhibitors / pharmacokinetics
  • Protease Inhibitors / pharmacology*
  • Stereoisomerism
  • Viral Nonstructural Proteins / antagonists & inhibitors*
  • Viral Nonstructural Proteins / metabolism

Substances

  • NS3 protein, hepatitis C virus
  • Protease Inhibitors
  • Viral Nonstructural Proteins