Preparation of fused purine derivatives as adenosine A3 receptor modulators.

Adenosine A3 receptor modulators of formulas I [R1, R2 = H, alkyl, aralkyl, aryl, etc.; R3 = aryl, alkyl, aralkyl; R4 = H, alkyl, aralkyl, aryl; X = CH, N] and II [R5, R6 = H, alkyl, aralkyl, aryl, etc.; R7 = alkyl, aryl, aralkyl; R8 = alkyl, aralkyl, aryl] are prepd. These compds. are useful as therapeutic agents for a no. of diseases and medical conditions that are mediated by the A3 receptor. The compds. of this invention are also useful as diagnostic agents for the A3 receptor. Thus, III was prepd., and had Ki value of 200 nM for binding to A3 receptors expressed in CHO cells.