Design, synthesis and biological evaluation of pyridine-phenylpiperazines: a novel series of potent and selective alpha1a-adrenergic receptor antagonist

Bioorg Med Chem. 2000 Sep;8(9):2263-75. doi: 10.1016/s0968-0896(00)00151-6.

Abstract

Beginning from the screening hit and literature alpha1-adrenergic compounds, a hybridized basic skeleton A was proposed as the pharmacophore for potent and selective alpha1a-AR antagonists. Introduction of a hydroxy group to increase the flexibility afforded B which served as the screening model and resulted in the identification of the second-generation lead 1. Using the Topliss approach, a number of potent and selective alpha1a-AR antagonists were discovered. In all cases, binding affinity and selectivity at the alpha1a-AR of S-hydroxy enantiomers were higher than the R-hydroxy enantiomers. As compared to the des-hydroxy analogues, the S-hydroxy enantiomers displayed comparable potency and better selectivity at alpha1a-AR. The S-hydroxy enantiomer 17 (Ki = 0.79 nM; alpha1b/alpha1a = 800; alpha1d/alpha1a = 104) was slightly less potent but much more selective at alpha1a-AR than tamsulosin (Ki = 0.13 nM, alpha1b/alpha1a = 15, alpha1d/alpha1a = 1.4). Compound 17 displayed higher selectivity in inhibiting rat prostate contraction over rat aorta contraction and also exhibited a higher degree of uroselectivity than tamsulosin in the anesthetized dog model.

MeSH terms

  • Adrenergic alpha-1 Receptor Antagonists
  • Adrenergic alpha-Antagonists / chemical synthesis
  • Adrenergic alpha-Antagonists / pharmacology
  • Animals
  • Aorta / drug effects
  • Binding, Competitive
  • Blood Pressure / drug effects
  • Combinatorial Chemistry Techniques
  • Dogs
  • Dose-Response Relationship, Drug
  • Humans
  • Kinetics
  • Male
  • Models, Animal
  • Muscle Contraction / drug effects
  • Piperazines / chemical synthesis*
  • Piperazines / pharmacology*
  • Prostate / drug effects
  • Protein Binding
  • Pyridines / chemical synthesis*
  • Pyridines / chemistry
  • Pyridines / pharmacology*
  • Rats
  • Rats, Long-Evans
  • Receptors, Adrenergic, alpha-1
  • Stereoisomerism
  • Structure-Activity Relationship
  • Sulfonamides / chemistry
  • Sulfonamides / pharmacology
  • Tamsulosin
  • Vasoconstrictor Agents / chemical synthesis
  • Vasoconstrictor Agents / pharmacology

Substances

  • ADRA1A protein, human
  • Adra1a protein, rat
  • Adrenergic alpha-1 Receptor Antagonists
  • Adrenergic alpha-Antagonists
  • Piperazines
  • Pyridines
  • Receptors, Adrenergic, alpha-1
  • Sulfonamides
  • Vasoconstrictor Agents
  • Tamsulosin
  • phenylpiperazine
  • pyridine