Alzheimer's disease treatment drug

Object of the present invention is to develop a highly safe substance use secretase inhibition of Alzheimer's disease treatment, provides the following general formula (I) or a salt thereof represented by the formula, A represents phenyl, R1 represents a chlorine atom, etc., a bromine atom, or a nitro group, R2, R3, R4 and R5 represents a hydrogen atom, L represents CH2-CH2 or CH = CH.