Patent ID: 7157465

Claim:
An adenine derivative, a tautomer thereof, or a pharmaceutically acceptable salt thereof represented by formula (I): wherein X represents NR 3 (wherein R 3 represents a hydrogen atom or C 1-3 alkyl), an oxygen atom, or a sulfur atom; R 1 represents substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted cycloalkyl, or substituted or unsubstituted cycloalkenyl; R 2 represents hydroxyl, mercapto, C 1-8 acyloxy, or C 2-8 alkoxycarbonyloxy; and Y represents a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted 5- or 6-membered monocyclic aromatic hetero ring containing 1 or 2 hetero atoms selected from the group consisting of nitrogen, oxygen, and sulfur atoms, or a substituted or unsubstituted fused bicyclic aromatic hetero ring containing 1 or 2 hetero atoms selected from the group consisting of nitrogen, oxygen, and sulfur atoms.