A compound represented by the general formula:or a pharmaceutically acceptable salt thereof or a solvate thereof, wherein Ring A is a C6-14 aryl group or the like, L is -NReCO- or the like (wherein Re is a hydrogen atom or the like), Ring B is a C6-14 aryl group or the like, X is a C1-3 alkylene group or the like, Y is a single bond or the like, Z is a C1-3 alkylene group or the like, R1 and R2 are each independently a hydrogen atom or the like, and R3, R4, R5 and R6 are independently a hydrogen atom, a halogen atom or the like, has an Aβ production inhibitory effect or a BACE1 inhibitory effect and is useful as a prophylactic or therapeutic agent for a neurodegenerative disease caused by Aβ and typified by Alzheimer-type dementia.
