InChI=1/C18H14N2O8/c21-14-6-9-5-13(18(27)28)20(12(9)7-15(14)22)2-1-8-3-10(16(23)24)19-11(4-8)17(25)26/h1-3,6-7,11,13H,4-5H2,(H3,23,24,25,26,27,28)/p-2