A salt of the compound represented by the following formula (I): (whereinR1 represents a
hydrogen atom, a
halogen atom, an amino group, R11-NH- (wherein R11 represents a C1-6
alkyl group, a hydroxy C1-6
alkyl group, a C1-6 alkoxy C1-6
alkyl group, or a C1-6 alkoxycarbonyl C1-6 alkyl group), R12-(CO)-NH- (wherein R12 represents a C1-6 alkyl group or a C1-6 alkoxy C1-6 alkyl group), a C1-6 alkyl group, a hydroxy C1-6 alkyl group, a cyano C1-6 alkyl group, a C1-6
alkoxy group, or a C1-6 alkoxy C1-6 alkyl group;R2 represents a
hydrogen atom, a C1-6 alkyl group, an amino group, or a di-C1-6 alkylamino group;one of X and Y represents a
nitrogen atom, and the other represents a
nitrogen atom or an
oxygen atom;ring A represents a 5- or 6-membered heteroaryl ring or a
benzene ring, which may have one or two
halogen atoms or C1-6 alkyl groups;Z represents a
single bond, a
methylene group, an
ethylene group, an
oxygen atom, a
sulfur atom, -CH2O-, -OCH2-, -NH-, -CH2NH-, -NHCH2-, -CH2S-, or -SCH2-;R3 represents a
hydrogen atom or a
halogen atom, or a C1-6 alkyl group, a C3-8 cycloalkyl group, a C6-10
aryl group, a 5- or 6-membered heteroaryl group, or a 5- or 6-membered non-aromatic heterocyclic group, wherein these groups may have one or two substituents selected from
substituent group α; andR4 represents a
hydrogen atom or a halogen atom;[
substituent Group α]a halogen atom, a cyano group, a C1-6 alkyl group, a C1-6
alkoxy group, a C1-6 alkoxycarbonyl group, a C3-8 cycloalkyl group, a C2-6 alkenyl group, and a C2-6 alkynyl group).