Disclosed is a compound represented by the formula (I) below or a pharmac ologically acceptable salt thereof. Also disclosed is a use of the compound or salt as a pharmaceutical product. (I) (In the formula, Ar1 represents a t riazolyl group or the like which may be substituted with a C1-6 alkyl group or the like; Ar2 represents a phenyl group or the like which may be substitu ted with a C1-6 alkoxy group or the like; X1 represents -CR3=CR4- (wherein R 3 and R4 respectively represent a C1-6 alkyl group or the like); and R1 and R2 respectively represent a C1 - 6 alkyl group or the like.)
