PURINE DERIVATIVES AND MEDICINE CONTAINING THE SAME AS THE ACTIVE INGREDIENT

摘要

Purine derivatives represented by the following formula and salts thereof: <CHEM> wherein R<1> represents a C1-C4 alkyl group or difluoromethyl group; R<2> represents tetrahydrofuranyl group, a C1-C7 alkyl group and the like; X represents hydrogen atom, a halogen atom or nitro group; and A represents a group represented by the following formula: <CHEM> wherein R<3> represents hydrogen atom, a halogen atom and the like; R<4> and R<5> represent hydrogen atom, a halogen atom, a C1-C4 alkyl group, a C1-C4 alkoxyl group and the like, which are useful as active ingredients of medicaments such as antiasthmatic agents.