Patent ID: 7834182

Claim:
A compound of the formula (I): wherein: X 1 represents a nitrogen atom; X 2 represents a nitrogen atom; X 3 represents —O s —(CH 2 ) m —, wherein s indicates 0 or 1, and m indicates an integer to make (m+s)=0, 1, 2, 3 or 4; R 1 and R 2 independently represent a hydrogen atom, a halogen atom, a linear or branched lower alkyl group, a lower alkoxy group, or an acetyl group substituted with 2 or 3 fluorine atoms; Y represents a phenyl group, a naphthyl group or a pyridyl group, which is unsubstituted or substituted with a substituent selected from a group consisting of a cyano group, a hydroxyl group, a lower alkyl group (the lower alkyl group may be further substituted with a hydroxyl group, a halogen atom, an amino group, an aryl group or a heteroaryl group), a cycloalkyl group, a lower alkoxy group (the lower alkoxy group may be further substituted with a halogen atom), a halogen atom, a mono-lower alkylcarbamoyl group, a di-lower alkylcarbamoyl group, a carbamoyl group, a cycloalkyliminocarbamoyl group, a lactam ring, a trifluoromethyl group, a mono-lower alkylamino group, a di-lower alkylamino group and an alkanoyl group; or a pharmaceutically-acceptable salt thereof.