Exploring the Directionality of 5-Substitutions in a New Series of 5-Alkylaminopyrazolo[4,3-<i>e</i>]1,2,4-triazolo[1,5-<i>c</i>]pyrimidine as a Strategy To Design Novel Human A<sub>3</sub> Adenosine Receptor Antagonists.
作者:Stephanie Federico、Antonella Ciancetta、Davide Sabbadin、Silvia Paoletta、Giorgia Pastorin、Barbara Cacciari、Karl Norbert Klotz、Stefano Moro、Giampiero Spalluto
DOI:10.1021/jm300899q
日期:2012.11.26
The structure-activity relationship (SAR) of new 5-alkylaminopyrazolo[4,3-e]1,2,4-triazolo[1,5-c]pyrimidines as antagonists of the A(3) adenosine receptor (AR) was explored with the principal aim to establish the directionality of 5-substitutions inside the orthosteric binding site of the A(3) AR. All the synthesized compounds showed affinity for the hA(3) AR from nanomolar to subnanomolar range. In particular, the most potent and selective antagonist presents an (S) alpha-phenylethylamino moiety at the 5 position (26, K-i hA(3) = 0.3 nM). Using an in silico receptor-driven approach, we have determined the most favorable orientation of the substitutions at the 5 position of the pyrazolo[4,3-e]1,2,4-triazolo[1,5-c]pyrimidine (PTP) scaffold, opening the possibility for further derivatizations aimed at directing the N-5 position toward the extracellular environment.