A compound represented by formula (I) or a pharmaceutically acceptable salt thereof. (In formula (I): L represents NR2R3, SR7, SO2R8, a substituted or unsubstituted alkyl, or a substituted or unsubstituted alkenyl； R2 represents a hydrogen atom, a substituted or unsubstituted alkyl, a substituted or unsubstituted alkenyl, a substituted or unsubstituted alkynyl, or the like； R3 represents a substituted or unsubstituted alkyl, a substituted or unsubstituted alkenyl, a substituted or unsubstituted alkynyl, or the like； R7 represents a hydrogen atom, a substituted or unsubstituted alkyl, a substituted or unsubstituted alkenyl, a substituted or unsubstituted alkynyl, or the like； R8 represents a hydrogen atom, a substituted or unsubstituted alkyl (but not an unsubstituted methyl or an unsubstituted ethyl), a substituted or unsubstituted alkenyl, a substituted or unsubstituted alkynyl, or the like； Y represents a substituted or unsubstituted alkyl (but not an unsubstituted methyl or an unsubstituted ethyl), a substituted or unsubstituted alkenyl, a substituted or unsubstituted alkynyl, a substituted or unsubstituted aryl, or the like； Z represents CR6= or N=； R1 represents a hydrogen atom or a substituted or unsubstituted alkyl； and R4, R5, and R6 are each independently a hydrogen atom, a halogen, a hydroxyl, a cyano, a nitro, a carboxy, a substituted or unsubstituted alkyl, a substituted or unsubstituted alkenyl, a substituted or unsubstituted alkynyl, or the like.)
