Rational design, synthesis, and pharmacological evaluation of 2-azanorbornane-3-exo,5-endo-dicarboxylic acid: a novel conformationally restricted glutamic acid analogue

J Org Chem. 2003 Feb 21;68(4):1489-95. doi: 10.1021/jo026509p.

Abstract

The design and synthesis of conformationally restricted analogues of alpha-amino acids is an often used strategy in medicinal chemistry research. Here we present the rational design, synthesis, and pharmacological evaluation of 2-azanorbornane-3-exo,5-endo-dicarboxylic acid (1), a novel conformationally restricted (S)-glutamic acid (Glu) analogue intended as a mimic of the folded Glu conformation. The synthesis of 1 was completed in its racemic form in eight steps from commercially available starting materials. As a key step, the first facially selective hydroboration of a 5-methylidene[2.2.1]bicyclic intermediate was investigated. In this transformation, the catalytic methodology of Wilkinson's/catechol borane proved superior to stoichiometric borane or dialkyl borane reagents, in terms of higher diastereomeric excess and chemical yield. To our surprise (+/-)-1 did not show affinity in binding studies on native 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) (IC(50) > 300 microM, [(3)H]AMPA) or kainic acid (IC(50) > 160 microM, [(3)H]kainic acid) receptors nor in binding studies on the cloned iGluR5,6 subtypes (IC(50) > 300 microM, [(3)H]kainic acid).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aza Compounds / chemical synthesis*
  • Aza Compounds / pharmacology*
  • Dicarboxylic Acids / chemical synthesis*
  • Dicarboxylic Acids / pharmacology*
  • Glutamic Acid* / analogs & derivatives
  • Glutamic Acid* / chemistry
  • Glutamic Acid* / pharmacology
  • Inhibitory Concentration 50
  • Kainic Acid / pharmacology
  • Magnetic Resonance Spectroscopy
  • Molecular Conformation
  • Molecular Mimicry
  • Molecular Structure
  • Norbornanes / chemical synthesis*
  • Norbornanes / pharmacology*
  • Receptors, Glutamate / chemistry*
  • Receptors, Glutamate / metabolism*
  • Stereoisomerism
  • Structure-Activity Relationship
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / pharmacology

Substances

  • 2-azanorbornane-3-exo,5-endo-dicarboxylic acid
  • Aza Compounds
  • Dicarboxylic Acids
  • Norbornanes
  • Receptors, Glutamate
  • Glutamic Acid
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
  • Kainic Acid