SYNTHESIS OF SOME TRICYCLIC HETEROAROMATIC SYSTEMS AND THEIR A(1) AND A(2A) ADENOSINE BINDING-ACTIVITY

The syntheses, A(1) and A(2a) adenosine receptor affinities and structure-activity relationships of some 2-aryl-1,2,4-triazolo[1,5-a]quinoxalines, 2-arylimidazo[1,2-a]quinoxalines, 1-arylimidazo[1,5-a]quinoxalines are reported and compared with that of a previously reported 2-phenylpyrazolo[1,5-a]quinoxaline. The results show that some triazoloquinoxalines are potent and specific A(1) adenosine receptor ligands and that the replacement of either nitrogen at position 1 or 3 of the triazoloquinoxaline moiety with a CH brought about a decrease in affinity at both adenosine receptors.