HEXAHYDROPYRROLOTHIAZINE COMPOUNDS

摘要

A compound of formula (I) or a pharmaceutically acceptable salt thereof, wherein R1 to R9 are as defined in the specification and which compound has an Alphabeta production inhibitory effect and may be useful as a prophylactic or therapeutic agent for a neurodegenerative disease caused by Alphabeta and typified by Alzheimer-type dementia (AD) or Down's syndrome.