| abstract |
A compound represented by the formula (I): n n n n n n n n n n or a pharmacologically acceptable salt thereof, wherein Ar 1 represents an imidazolyl group or the like which may be substituted with a C1-6 alkyl group, Ar 2 represents a phenyl group or the like which may be substituted with a C1-6 alkoxy group, X 1 represents a double bond or the like and Het represents a triazolyl group or the like which may be substituted with a C1-6 alkyl group or the like, is effective as a therapeutic or prophylactic agent for a disease caused by Aβ. |