New fluoro derivatives of the pyrazolo[5,1-c][1,2,4]benzotriazine 5-oxide system: evaluation of fluorine binding properties in the benzodiazepine site on γ-aminobutyrric acid type A (GABA(A)) receptor. Design, synthesis, biological, and molecular modeling investigation

J Med Chem. 2010 Nov 11;53(21):7532-48. doi: 10.1021/jm1001887.

Abstract

In the search for potent ligands at the benzodiazepine site on the GABA(A) receptor, new fluoro derivatives of the pyrazolo[5,1-c][1,2,4]benzotriazine system were synthesized to evaluate the importance of the introduction of a fluorine atom in this system. Biological and pharmacological studies indicate that the substitution at position 8 with a trifluoromethyl group confers pharmacological activity due to potential metabolic stability in comparison to inactive 8-methyl substituted analogues. In particular, the compound 3-(2-methoxybenzyloxycarbonyl)-8-trifluoromethylpyrazolo[5,1-c][1,2,4]benzotriazine 5-oxide (21) emerges because of its selective anxiolytic profile without side effects. An analysis of all the newly synthesized compounds in our pharmacophoric map confirms the essential interaction points for binding recognition and the important areas for affinity modulation. The fluorine atom was able to form a hydrogen bond interaction only when it is not in position 3.

MeSH terms

  • Animals
  • Anti-Anxiety Agents / chemical synthesis*
  • Anti-Anxiety Agents / chemistry
  • Anti-Anxiety Agents / pharmacology
  • Binding Sites
  • Cattle
  • Cerebral Cortex / metabolism
  • Crystallography, X-Ray
  • Drug Design
  • Drug Inverse Agonism
  • In Vitro Techniques
  • Male
  • Mice
  • Models, Molecular*
  • Molecular Structure
  • Pyrazoles / chemical synthesis*
  • Pyrazoles / chemistry
  • Pyrazoles / pharmacology
  • Radioligand Assay
  • Rats
  • Rats, Wistar
  • Receptors, GABA-A / metabolism*
  • Structure-Activity Relationship
  • Triazines / chemical synthesis*
  • Triazines / chemistry
  • Triazines / pharmacology

Substances

  • 3-(2-methoxybenzyloxycarbonyl)-8-trifluoromethylpyrazolo(5,1-c)(1,2,4)benzotriazine 5-oxide
  • Anti-Anxiety Agents
  • Pyrazoles
  • Receptors, GABA-A
  • Triazines