To develop a highly safe measure to treat Alzheimer's disease using a secretase-inhibiting substance, there is provided a compound represented by the following general formula (I) or a salt thereof: wherein A represents a phenyl group or the like, R 1 represents a chlorine atom, a bromine atom, or a nitro group or the like, R 2 , R 3 , R 4 , and R 5 each represent a hydrogen atom or the like, and L represents CH 2 -CH 2 or CH=CH.