Pyrazolo-triazolo-pyrimidines as adenosine receptor antagonists: A complete structure–activity profile

In the last 5 years, many efforts have been conducted searching potent and selective human A3 adenosine antagonists. In this field several different classes of compounds, possessing very good affinity (nM range) and with a broad range of selectivity, have been proposed. Recently, our group synthesized a new series of pyrazolo-triazolo-pyrimidines bearing different substitutions at the N5 and N8 positions, which have been described as highly potent and selective human A3 adenosine receptor antagonists. The present review summarizes available data and provides an overview of the structure–activity relationships found for this class of human A3 adenosine receptor antagonists.