The present invention provides a compound which has an effect of inhibiting amyloid ßproduction, especially an effect of inhibiting BACE1, and which is useful as a therapeutic or prophylactic agent for diseases induced by production, secretion and/or deposition of amyloid ßproteins.
A compound of Formula (I) wherein R3 is each independently alkyl optionally substituted with halogen, cyano, alkyloxy, haloalkyloxy or non-aromatic carbocyclyl, or the like; t is integer from 0 to 3; R5 is a hydrogen atom or halogen; R6 is selected from the group consisting of a hydrogen atom, halogen, and substituted or unsubstituted alkyl; ring B is a substituted or unsubstituted pyrazine or the like; or a pharmaceutically acceptable salt thereof.