The Influence of the 1-(3-Trifluoromethyl-Benzyl)-1H-Pyrazole-4-yl Moiety on the Adenosine Receptors Affinity Profile of Pyrazolo[4,3-e][1,2,4]Triazolo[1,5-c]Pyrimidine Derivatives

PLoS One. 2015 Dec 1;10(12):e0143504. doi: 10.1371/journal.pone.0143504. eCollection 2015.

Abstract

A new series of pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine (PTP) derivatives has been developed in order to explore their affinity and selectivity profile at the four adenosine receptor subtypes. In particular, the PTP scaffold was conjugated at the C2 position with the 1-(3-trifluoromethyl-benzyl)-1H-pyrazole, a group believed to confer potency and selectivity toward the human (h) A2B adenosine receptor (AR) to the xanthine ligand 8-(1-(3-(trifluoromethyl)benzyl)-1H-pyrazol-4-yl)-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione (CVT 6975). Interestingly, the synthesized compounds turned out to be inactive at the hA2B AR but they displayed affinity at the hA3 AR in the nanomolar range. The best compound of the series (6) shows both high affinity (hA3 AR Ki = 11 nM) and selectivity (A1/A3 and A2A/A3 > 9090; A2B/A3 > 909) at the hA3 AR. To better rationalize these results, a molecular docking study on the four AR subtypes was performed for all the synthesized compounds. In addition, CTV 6975 and two close analogues have been subjected to the same molecular docking protocol to investigate the role of the 1-(3-trifluoromethyl-benzyl)-1H-pyrazole on the binding at the four ARs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CHO Cells
  • Cricetinae
  • Cricetulus
  • Humans
  • Models, Molecular
  • Protein Binding
  • Protein Conformation
  • Purinergic P1 Receptor Antagonists / chemistry*
  • Purinergic P1 Receptor Antagonists / metabolism*
  • Purinergic P1 Receptor Antagonists / pharmacology
  • Pyrazoles / chemistry*
  • Pyrimidines / chemistry*
  • Pyrimidines / metabolism*
  • Pyrimidines / pharmacology
  • Receptors, Purinergic P1 / chemistry
  • Receptors, Purinergic P1 / metabolism*
  • Structure-Activity Relationship

Substances

  • Purinergic P1 Receptor Antagonists
  • Pyrazoles
  • Pyrimidines
  • Receptors, Purinergic P1
  • pyrazole
  • pyrimidine

Grants and funding

This work was supported by: Italian Ministry for University and Research, PRIN2008: protocol number 200834TC4L_002 (SM) and protocol number 200834TC4L_004 (GS SF); http://prin.miur.it/index.php?pag=2008. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.