| abstract |
The present invention relates to a compound of the formula (1): n nwherein R 1 is group of the formula (2):n n n(wherein X is nitrogen atom or C(R 5 ), Y is nitrogen atom or C(R 6 ), R 5 and R 6 are each independently hydrogen atom, etc.) etc., m is 1 to 6, L 1 is single bond, etc., R 2 is hydrogen atom, substituted or unsubstituted alkyl group, etc., R 3 is hydrogen atom, etc., L 2 is single bond, etc., R 4 is hydrogen atom, substituted or unsubstituted aryl group, etc., or pharmaceutically acceptable salt thereof, being useful for preventing or treating Alzheimer's disease. |