| abstract |
Disclosed is a compound represented by the formula (I) or a pharmacologically acceptable salt thereof: (I) wherein Ar1 represents an imidazolyl group which may be substituted by a C1-6 alkyl group, or the like; Ar2 represents a phenyl group which may be substituted by a C1-6 alkoxy group, or the like; X1 represents a double bond or the like; and Het represents an imidazolyl group which may be substituted by a C1-6 alkyl group or the like, or the like. The compound or the salt is effective as a therapeutic or prophylactic agent for a disease associated with A.beta.. |