Scaffold-hopping identifies furano[2,3-d]pyrimidine amides as potent Notum inhibitors

Bioorg Med Chem Lett. 2020 Feb 1;30(3):126751. doi: 10.1016/j.bmcl.2019.126751. Epub 2019 Oct 28.


The carboxylesterase Notum is a key negative regulator of the Wnt signaling pathway by mediating the depalmitoleoylation of Wnt proteins. Our objective was to discover potent small molecule inhibitors of Notum suitable for exploring the regulation of Wnt signaling in the central nervous system. Scaffold-hopping from thienopyrimidine acids 1 and 2, supported by X-ray structure determination, identified 3-methylimidazolin-4-one amides 20-24 as potent inhibitors of Notum with activity across three orthogonal assay formats (biochemical, extra-cellular, occupancy). A preferred example 24 demonstrated good stability in mouse microsomes and plasma, and cell permeability in the MDCK-MDR1 assay albeit with modest P-gp mediated efflux. Pharmacokinetic studies with 24 were performed in vivo in mouse with single oral administration of 24 showing good plasma exposure and reasonable CNS penetration. We propose that 24 is a new chemical tool suitable for cellular studies to explore the fundamental biology of Notum.

Keywords: CNS penetration; Furano[2,3-d]pyrimidines; Notum inhibitor; SBDD; Wnt signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylesterase / antagonists & inhibitors*
  • Acetylesterase / metabolism
  • Amides / chemistry*
  • Amides / metabolism
  • Amides / pharmacology
  • Animals
  • Binding Sites
  • Cell Membrane Permeability / drug effects
  • Crystallography, X-Ray
  • Dogs
  • Half-Life
  • Inhibitory Concentration 50
  • Madin Darby Canine Kidney Cells
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Microsomes / metabolism
  • Molecular Dynamics Simulation
  • Protein Structure, Tertiary
  • Pyrimidines / chemistry*
  • Structure-Activity Relationship
  • Wnt Signaling Pathway / drug effects


  • Amides
  • Pyrimidines
  • Acetylesterase
  • pyrimidine