Patent ID: RE39112

Claim:
A purine compound represented by the formula (I), or its pharmacologically acceptable salt thereof, wherein in the formula (I), R 1 represents: 1) formula: wherein X is a hydrogen atom, a hydroxyl group, an optionally substituted lower alkyl group, an optionally substituted lower alkoxy group, an optionally substituted aryl group, an optionally substituted heteroaryl group, an optionally substituted acyl group, an optionally substituted acyloxy group or an optionally substituted amino group; and R 5 and R 6 are the same as or different from each other and each represents a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted saturated or unsaturated C 3-8 cycloalkyl group, an optionally substituted C 3-8 cycloalkyl-C 2-6 alkyl group, an optionally substituted aryl group, an optionally substituted heteroaryl group, an optionally protected carboxyl group or an optionally substituted four- to six-membered ring having at least one hetero atom; optionally R 5 and R 6 is either an oxygen atom or a sulfur atom together, or R 5 and R 6 are a ring which may have a hetero atom being formed together with a carbon atom to which they are bonded; wherein said ring may be substituted; or 2) a five- or six-membered aromatic ring that may have a substituent group and a hetero atom; W represents formula —CH 2 CH 2 —, —CH═CH— or —C≡C—; R 2 represents a hydrogen atom, an optionally substituted lower alkyl group, a hydroxyl group or a formula —NR 7 R 8 , wherein R 7 and R 8 are the same as or different from each other and each represents a hydrogen atom, a hydroxyl group, an optionally substituted lower alkyl group, and optionally substituted acyl group, an optionally substituted C 3-8 cycloalkyl group, an optionally substituted aryl group or an optionally substituted heteroaryl group; optionally R 7 and R 8 are a saturated ring which is formed together with a nitrogen atom to which they are bonded, said saturated ring is selected from the group consisting of aziridine, azetidine, pyrrolidine, piperidine, perhydroazepine, perhydroazocine, piperazine, homopiperazine, morpholine and thiomorpholine; wherein the ring optionally has a substituent selected from the group consisting of a lower alkyl group, a halogen and an acyl group; R 3 represents an optionally substituted C 3-8 cycloalkyl group, an optionally substituted aryl group, an optionally substituted heteroaryl group or an optionally substituted C 2-6 alkenyl group; and R 4 represents a hydrogen atom, an optionally substituted lower alkyl group, an optionally substituted C 3-8 cycloalkyl group, an optionally substituted aryl group, an optionally substituted heteroaryl group, an optionally substituted C 2-6 alkenyl group, an optionally substituted C 2-6 alkynyl group or an optionally substituted cyclic ether group; wherein when W is —CH 2 CH 2 —, then X is not a hydrogen atom or an alkyl group.