Structure-activity relationships for a novel series of dopamine D2-like receptor ligands based on N-substituted 3-aryl-8-azabicyclo[3.2.1]octan-3-ol

J Med Chem. 2008 Oct 9;51(19):6095-109. doi: 10.1021/jm800532x. Epub 2008 Sep 6.

Abstract

Discovering dopamine D2-like receptor subtype-selective ligands has been a focus of significant investigation. The D2R-selective antagonist 3-[4-(4-chlorophenyl)-4-hydroxypiperidinyl]methylindole (1, L741,626; K(i)(D2R/D3R) = 11.2:163 nM) has previously provided a lead template for chemical modification. Herein, analogues have been synthesized where the piperidine was replaced by a tropane ring that reversed the selectivity seen in the parent compound, in human hD2(L)R- or hD3R-transfected HEK 293 cells (31, K(i)(D2R/D3R) = 33.4:15.5 nM). Further exploration of both N-substituted and aryl ring-substituted analogues resulted in the discovery of several high affinity D2R/D3R ligands with 3-benzofurylmethyl-substituents (e.g., 45, K(i)(D2R/D3R) = 1.7:0.34 nM) that induced high affinity not achieved in similarly N-substituted piperidine analogues and significantly (470-fold) improved D3R binding affinity compared to the parent ligand 1. X-ray crystallographic data revealed a distinctive spatial arrangement of pharmacophoric elements in the piperidinol vs tropine analogues, providing clues for the diversity in SAR at the D2 and D3 receptor subtypes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Azabicyclo Compounds / chemical synthesis
  • Azabicyclo Compounds / chemistry
  • Azabicyclo Compounds / pharmacology*
  • Binding Sites
  • Crystallography, X-Ray
  • Ligands
  • Models, Molecular
  • Molecular Structure
  • Receptors, Dopamine D2 / chemistry
  • Receptors, Dopamine D2 / drug effects*
  • Stereoisomerism
  • Structure-Activity Relationship

Substances

  • Azabicyclo Compounds
  • Ligands
  • Receptors, Dopamine D2