Pyrazolo-triazolo-pyrimidine derivatives as adenosine receptor antagonists: A possible template for adenosine receptor subtypes?

A review. Adenosine, a widely distributed modulator, regulates many physiol. functions through specific cell membrane G-protein-coupled receptors classified as A1, A2A, A2B and A3. An intense medicinal chem. effort made over the last 20 yr has led to a variety of selective adenosine receptor agonists and antagonists. In particular, the pyrazolo-triazolo-pyrimidine nucleus has been strongly investigated in the last years by our group. All the modifications performed and a tentative of structure-activity-relation is reported. In fact, the combination of different substitutions at the N7, N8 and N5 positions afford compds. which showed good affinity and selectivity for the different adenosine receptor subtypes. The data herein summarized, permit to speculate on the use of this nucleus as possible template for the adenosine receptor subtypes.