Patent ID: 8912181

Claim:
A compound represented by formula (I) or a salt thereof: wherein at least one of X 1 , X 2 , X 3 , and X 4 represents N or N-oxide and the rest thereof are the same or different and each represent C—R 2 ; any one or two of Y 1 , Y 2 , Y 3 , and Y 4 represent C—R 4 and the rest thereof are the same or different and each represent CH or N; R 1 represents an optionally substituted monocyclic or bicyclic unsaturated heterocyclic group having 1 to 4 heteroatoms selected from the group consisting of N, S, and O; R 2 represents a hydrogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted cycloalkyl group having 3 to 7 carbon atoms, or an optionally substituted alkenyl group having 2 to 6 carbon atoms; R 3 represents a cyano group, or —CO—R 5 ; R 4 represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, —CO—R 6 , —N(R 7 )(R 8 ), or —S—R 9 ; R 5 represents a hydroxyl group, an amino group, or an optionally substituted alkylamino group having 1 to 6 carbon atoms; R 6 represents a hydroxyl group, an amino group optionally having a hydroxyl group, or an optionally substituted alkylamino group having 1 to 6 carbon atoms; R 7 and R 8 are the same or different and each represent a hydrogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted cycloalkyl group having 3 to 7 carbon atoms, an optionally substituted aromatic hydrocarbon group, an optionally substituted saturated heterocyclic group, or an optionally substituted unsaturated heterocyclic group, or R 7 and R 8 together form a saturated heterocyclic group together with the nitrogen atom bonded thereto; and R 9 represents an optionally substituted cycloalkyl group having 3 to 7 carbon atoms, or an optionally substituted aromatic hydrocarbon group.