The invention relates to compounds of formula
wherein R
1
, R
1′
, R
2
, R
3
, n, A, and hetaryl are defined herein or to pharmaceutically active acid addition salts thereof. The present compounds of formula I are modulators for amyloid beta and thus, they may be useful for the treatment or prevention of a disease associated with the deposition of β-amyloid in the brain, in particular Alzheimer's disease, and other diseases such as cerebral amyloid angiopathy, hereditary cerebral hemorrhage with amyloidosis, Dutch-type (HCHWA-D), multi-infarct dementia, dementia pugilistica and Down syndrome.