FUSED PURINE DERIVATIVES

摘要

Fused purine derivatives represented by general formula (I) or pharmacologically acceptable salts thereof, which show an adenosine A3 receptor antagonism and have, for example, antiasthmatic, bronchodilating and itch-relieving effects. In said formula, R<1> represents optionally substituted aryl or an optionally substituted aromatic heterocyclic group; R<2> represents hydrogen, lower alkyl, alicyclic alkyl, optionally substituted aralkyl, optionally substituted aryl, or an optionally substituted aromatic heterocyclic group; R<3> represents hydrogen, lower alkyl or optionally substituted aralkyl; X<1> and X<2> are the same or different and each represents hydrogen, lower alkyl, optionally substituted aralkyl, or optionally substituted aryl; and n is an integer of 0 to 3.