As for this invention, formula (i): [Conversion 1](In formula, R1 and R2 independently the aryl which is possible to have possessed the aryl oxy or the substituent which is possible to have possessed the substituent is thio, R3 regards the medicine composition which can be utilized effectively to the prevention or remedy of the disease and the especially arutsuhaima symptom where extended type amyloid participates it is the hydrogen atom or the low-grade alkyl group) with the medicine composition which designates the salt or those solvent dishes dressed with sauce which on chemical compound or the medicine manufacture which are shown is allowed as the active ingredient, on the basis of the extension type amyloid production control action of especially above-mentioned chemical compound. In addition this invention regards the reagent in order the screening to do the extended type amyloid production deterrent.本発明は、式(I):[化1](式中、R1およびR2は各々独立して置換基を有していてもよいアリールオキシまたは置換基を有していてもよいアリールチオであり、R3は水素原子または低級アルキル基である)で示される化合物若しくはその製薬上許容される塩、またはそれらの溶媒和物を有効成分とする医薬組成物、特に上記化合物の延長型アミロイドβ産生抑制作用に基づいて、延長型アミロイドβが関与する疾患、特にアルツハイマー症の予防または治療に有効に利用できる医薬組成物に関する。また本発明は延長型アミロイドβ産生抑制物質をスクリーニングするための試薬に関する。
