The present invention relates to a compound of formula I, I-1 or I-2 wherein R1is hydrogen, lower alkyl, lower alkyl substituted by halogen, halogen, lower alkoxy, or lower alkoxy substituted by halogen； R1may be different if n = 2 or 3 n is 1, 2 or 3 Ar is a six membered heteroaryl group, selected from； wherein R2is hydrogen, lower alkyl, lower alkyl substituted by halogen, halogen or lower alkoxy； R3is hydrogen or halogen； or to a pharmaceutically active acid addition salt thereof. The compounds may be used for the treatment of Alzheimer’s disease, cerebral amyloid angiopathy, hereditary cerebral hemorrhage with amyloidosis, Dutch-type (HCHWA-D), multi-infarct dementia, dementia pugilistica or Down syndrome.本發明係關於式I、I-1或I-2之化合物 其中 R1係氫、低碳數烷基、經鹵素取代之低碳數烷基、鹵素、低碳數烷氧基或經鹵素取代之低碳數烷氧基； 若n = 2或3，則R1可不同 n 係1、2或3 Ar 係6員雜芳基，其選自； 其中 R2係氫、低碳數烷基、經鹵素取代之低碳數烷基、鹵素或低碳數烷氧基； R3係氫或鹵素； 或係關於其醫藥活性酸加成鹽。 該等化合物可用於治療阿茲海默氏病(Alzheimer’s disease)、腦類澱粉血管病變、荷蘭型遺傳性腦出血伴類澱粉變性(hereditary cerebral hemorrhage with amyloidosis, Dutch-type，HCHWA-D)、多發性梗塞失智症、拳擊手型失智症或唐氏症候群(Down syndrome)。
