Novel compound having affinity for amyloid

A compound represented by the following formula (3), or a salt thereof:

• wherein R9 is a group selected from the group consisting of a non-radioactive halogen substituent, a nitro group, a trialkylstannyl substituent having alkyl chains with 1 to 4 carbon atoms or a triphenylstannyl group,
• R6 is a group selected from the group consisting of a cyano substituent, an alkyl substituent with 1 to 4 carbon atoms and a halogen substituent, and
• R7 is a group selected from the group consisting of a hydroxyl group, a halogen substituent and a substituent represented by the following formula (4):
• wherein R8 is a hydrogen, a halogen substituent or a hydroxyl group, and m is an integer of 1 to 4.

A compound represented by the following formula (5), or a salt thereof:

• wherein R5 is a group selected from the group consisting of a halogen substituent, an alkyl substituent with 1 to 4 carbon atoms, an alkoxy substituent having an alkyl chain with 1 to 4 carbon atoms and a hydroxyl group,
• R10 is a group selected from the group consisting of a non-radioactive halogen substituent, a nitro group, a trialkylstannyl substituent having alkyl chains with 1 to 4 carbon atoms or a triphenylstannyl group, and
• R7 is a group selected from the group consisting of a hydroxyl group, a halogen substituent and a substituent represented by the following formula (4):
• wherein R8 is a hydrogen, a halogen substituent or a hydroxyl group, and n is an integer of 1 to 4.

A reagent for detecting amyloid deposited on a biological tissue, which comprises a compound represented by the following formula (1), or a salt thereof:

• wherein R1 is a group selected from the group consisting of a halogen substituent, an alkyl substituent with 1 to 4 carbon atoms, an alkoxy substituent having an alkyl chain with 1 to 4 carbon atoms and a hydroxyl group,
• R2 is a group selected from the group consisting of a cyano substituent, an alkyl substituent with 1 to 4 carbon atoms and a halogen substituent, and
• R3 is a group selected from the group consisting of a a hydroxyl group, a halogen substituent and a substituent represented by the following formula (2):
• wherein R4 is a hydrogen, a halogen substituent or a hydroxyl group, and m is an integer of 1 to 4, provided that at least one of R1, R2, R3 and R4 represents a radioactive halogen.