Synthesis and evaluation of estrogen receptor ligands with bridged oxabicyclic cores containing a diarylethylene motif: estrogen antagonists of unusual structure

J Med Chem. 2005 Nov 17;48(23):7261-74. doi: 10.1021/jm0506773.


A new series of ligands for the estrogen receptor (ER) based on a three-dimensional structural motif consisting of a bridged oxabicyclic core (7-oxabicyclo[2.2.1]heptene or heptadiene) were synthesized and examined for their receptor binding activity and as regulators of transcription through the two ER subtypes, ER alpha and ER beta. The prototypical ligands also contain a 1,2-diarylethylene motif, common to many nonsteroidal estrogens, as an embellishment on the oxabicyclic core. Thus, these ligands bear peripheral groups typically found in ER ligands, built here upon an overall three-dimensional core topology that is unusual for these targets. Most of these compounds were conveniently synthesized by a Diels-Alder reaction of various 3,4-diarylfurans with a variety of dienophiles, neat and under mild conditions in the absence of catalysts. Some of the synthesized compounds display good binding affinity for the ER, and in transcription assays, the highest affinity compounds are antagonists on both ERs. Molecular modeling studies suggest a structural basis for the antagonist activity of these compounds. These compounds, based on the bicyclo[2.2.1]core system, expand the structural diversity of ligands that can be antagonists for the estrogen receptors.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Binding Sites
  • Bridged Bicyclo Compounds, Heterocyclic / chemical synthesis*
  • Bridged Bicyclo Compounds, Heterocyclic / chemistry
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology
  • Cell Line, Tumor
  • Endometrial Neoplasms
  • Estrogen Receptor alpha / antagonists & inhibitors*
  • Estrogen Receptor alpha / genetics
  • Estrogen Receptor beta / antagonists & inhibitors*
  • Estrogen Receptor beta / genetics
  • Female
  • Heptanes / chemical synthesis*
  • Heptanes / chemistry
  • Heptanes / pharmacology
  • Humans
  • In Vitro Techniques
  • Ligands
  • Models, Molecular
  • Molecular Structure
  • Radioligand Assay
  • Stereoisomerism
  • Structure-Activity Relationship
  • Transcription, Genetic
  • Uterus / metabolism


  • Bridged Bicyclo Compounds, Heterocyclic
  • Estrogen Receptor alpha
  • Estrogen Receptor beta
  • Heptanes
  • Ligands