Novel Compound Having Affinity to Amyloid

A compound represented by the following formula (2), wherein A5, A6, A7 and A8 independently represent a carbon or a nitrogen, and

• R4 a group represented by the following formula:
• wherein m is an integer of 0 to 4;
• n is an integer of 0 or 1;
• and
• when m=n=0, R is a non-radioactive halogen substituent, nitro substituent, trialkylstannyl substituent having 3 to 12 carbon atoms or triphenylstannyl substituent, and when m≠0 and/or n≠0, R2 is a non-radioactive halogen substituent, methanesulfonyloxy substituent, trifluoromethanesulfonyloxy substituent or aromatic sulfonyloxy substituent, provided that at least one of A5, A6, A7 and A8 represents a carbon, and R4 binds to a carbon represented by A5, A6, A7 or A8.

A low-toxic diagnostic agent for Alzheimer's disease, which comprise a compound represented by the following formula (1) or a salt thereof:

• wherein A1, A2, A3 and A4 independently represents a carbon or a nitrogen, and
• R3 is a group represented by the following formula:
• wherein R1 is a radioactive halogen substituent;
• m is an integer of 0 to 4;
• and
• n is an integer of 0 or 1,
• provided that at least one of A1, A2, A3 and A4 represents a carbon and R3 binds to a carbon represented by A1, A2, A3 or A4.