Discovery of Potent Cyclophilin Inhibitors Based on the Structural Simplification of Sanglifehrin A

J Med Chem. 2017 Feb 9;60(3):1000-1017. doi: 10.1021/acs.jmedchem.6b01329. Epub 2017 Jan 31.


Cyclophilin inhibition has been a target for the treatment of hepatitis C and other diseases, but the generation of potent, drug-like molecules through chemical synthesis has been challenging. In this study, a set of macrocyclic cyclophilin inhibitors was synthesized based on the core structure of the natural product sanglifehrin A. Initial compound optimization identified the valine-m-tyrosine-piperazic acid tripeptide (Val-m-Tyr-Pip) in the sanglifehrin core, stereocenters at C14 and C15, and the hydroxyl group of the m-tyrosine (m-Tyr) residue as key contributors to compound potency. Replacing the C18-C21 diene unit of sanglifehrin with a styryl group led to potent compounds that displayed a novel binding mode in which the styrene moiety engaged in a π-stacking interaction with Arg55 of cyclophilin A (Cyp A), and the m-Tyr residue was displaced into solvent. This observation allowed further simplifications of the scaffold to generate new lead compounds in the search for orally bioavailable cyclophilin inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Chromatography, Liquid
  • Crystallography, X-Ray
  • Cyclophilins / antagonists & inhibitors*
  • Drug Discovery
  • Humans
  • Hydrogen Bonding
  • Lactones / chemistry
  • Lactones / pharmacology
  • Proton Magnetic Resonance Spectroscopy
  • Spectrometry, Mass, Electrospray Ionization
  • Spiro Compounds / chemistry
  • Spiro Compounds / pharmacology
  • Structure-Activity Relationship
  • Surface Plasmon Resonance
  • Thermodynamics


  • Lactones
  • Spiro Compounds
  • sanglifehrin A
  • Cyclophilins