| abstract |
The present invention provides a compound represented by formula (1A) or a pharmaceutically acceptable salt thereof. A compound represented by formula (1A) or a pharmaceutically acceptable salt thereof, wherein A 1 and A 2 are the same or different, and are each independently -C(=O)B, -C(=O)CR 3A R 3B B, -CO 2 B, -C(=S)OB, -CONR 3C B, -C(=S)NR 3C B, hydrogen atom, etc., wherein, A 1 and A 2 are not hydrogen atoms at the same time, wherein, B is an optionally substituted 3-membered to 12-membered monocyclic or polycyclic heterocyclic group, an optionally substituted 3-membered to 12-membered ring amino group, or a group represented by the following formula (B), wherein the 3-membered to 12-membered monocyclic or polycyclic heterocyclic group and the 3-membered to 12-membered ring amino group have at least one or more secondary nitrogen atoms in the ring; R 1 is a hydrogen atom or the like; R 2A , R 2B , R 2C and R 2D are the same or different, and are each independently a hydrogen atom or the like; and R 8 is an alkyl group. [chemical formula 1] [chemical formula 2] where * indicates the bonding position. |