Disclosed is a compound represented by formula (1) or a salt thereof,formula (1):wherein X is a residue of a compound having activity of binding to at least one member selected from the group consisting of amyloid β proteins, tau proteins, α-synuclein, and TDP-43 m is an integer of 0 to 6 n is an integer of 1 to 5 and J is a group selected from the group consisting ofwherein R1 and R2 are each independently a hydrogen atom, a fluorine atom, methyl, or trifluoromethyl R3 is trifluoromethyl or trifluoromethoxy and p is an integer of 1 to 4, provided that m+n≧5 when J is J-1, and m+n≧7 when J is J-2 or J-3.
