2-Aryl-8-chloro-1,2,4-triazolo[1,5-a]quinoxalin-4-amines as highly potent A1 and A3 adenosine receptor antagonists

The synthesis and bA1, bA2A, and hA3 adenosine receptor binding affinity of some 2-phenyl-1,2,4-triazolo[1,5-a]quinoxaline derivatives 2-18 bearing different substituents on either the 4-amino moiety (acyl or carbamoyl groups) or the 2-phenyl ring (4-OCH3) of previously reported 8-chloro-2-phenyl-1,2,4-triazolo[1,5-a]quinoxalin-4-amine (1), are described. Structure-activity relationships have been explained analyzing the three-dimensional structure of the antagonist-A3 receptor models obtained by molecular docking simulation.