InChI=1S/C18H14N4O6S/c23-15-7-5-14(6-8-15)21-20-13-3-1-12(2-4-13)19-17-10-9-16(29(26,27)28)11-18(17)22(24)25/h1-11,19,23H,(H,26,27,28)/b21-20+