To provide a compound that inhibits the formation of amyloid fibrils, an amyloid fibrils formation inhibitor containing the compound, and therapeutic or preventive agents for neurodegenerative diseases.SOLUTION: The present invention provides a compound represented by formula (I). [X is -(CH)- n is an integer of 0-3 Y is a single bond or a divalent linking group such as an alkyl group Ar is a substituted/unsubstituted phenyl group or pyridyl group Ris a substituted/unsubstituted alkyl group Ar and R, Ar and Y or Rand Y may form a ring together R-Rindependently represent H, a Calkyl group or the like].SELECTED DRAWING: None【課題】アミロイド線維の形成を抑制する化合物、当該化合物を含むアミロイド線維形成抑制剤および神経変性疾患の治療薬または予防薬の提供。【解決手段】式(I)で表される化合物。[Xは-(CH2)n-;nは0~3の整数;Yは単結合又はアルキル基等の2価の連結基;Arは置換/非置換のフェニル基又はピリグル基;R1は置換/非置換のアルキル基;Ar及びR1、Ar及びY又はR1及びYは、共同して環を形成してもよい;R2~R4は夫々独立にH、C1-20アルキル基等]【選択図】なし
