Prodrug or a pharmaceutically acceptable salt or a compound of formula (I): (I) [wherein, is CH or N X the Q, is O or NR 6 A 2 and A 1 may independently, can also form a carbonyl group or together are C 1-6 alkyl or hydrogen independently, R 2 and R 1 is hydrogen, halogen, CF 3, CN, OR more hydroxyl, C 1-6 alkoxy, or halogen or one or 10, SO 2 NR 8 R 9, SO 2 R 10, 7, OR 8, NR 8 R 9, NR 8 COR 10, NR 8 SO 2 R C 1-6 alkyl which is optionally substituted and independently by NR 8 R 9 is hydrogen, halogen, OR 7 or CF 3 R3 the R 4, hydrogen, halogen, CF 3, OR The C 1-6 alkyl which is optionally substituted by NR 8 R 9 or 1-6 alkoxy or hydroxyl 10, NR 8 SO 2 R 10,8, NR 8R 9, NR 8 COR, C or, R 3 and when R 4 is ortho-position to form (CH 2) m O- -O is 1 to 3 and m taken together R 5 are, NR 1-6 alkoxy or hydroxyl or hydrogen,, C The R 6,C 1-6 alkyl or hydrogen C 1-6 alkyl which is optionally substituted by hydrogen 8 R 9, or R 7 is optionally substituted by NR 8 R 9 or OR 8C 1-6 alkyl was C, which is optionally substituted by 1-6 alkoxy hydrogen, C 1-6 alkyl or hydroxyl, or a 1-3 alkyl phenyl C, and here, R 8 is the phenyl group is, it is optionally substituted by one or more substituents or is selected from halogen, C 1-6 alkyl, OCF 3, or 7, NR 8 R 9 CF 3, OR or and R 9 radicals R 8 , when they are attached to the nitrogen atom, six or five which is optionally substituted optionally containing one additional heteroatom selected from O and 7, S NR, by C 1-6 alkoxy, hydroxyl or if they are bound to the nitrogen atom, or, R 9 and groups R 8, together with the azetidinyl ring is optionally substituted by C 1-6 alkoxy or hydroxyl may form together membered ring R 10 is phenyl or C 1-6 alkyl optionally substituted by one or more substituents selected one halogen, C 1-6 alkyl, OR 7, or 3, OCF 3 CF may form n is 1 or 2 has a group. ]. The use of compounds in the treatment of amyloid diseases are also disclosed. [Selection] Figure Figure 1式(I)の化合物またはその薬学的に許容される塩またはプロドラッグ:(I)[式中、Xは、
