InChI=1S/C21H20N2O8/c1-9-4-16(27)18(21(29)31-9)15-6-13(20(28)30-8-11(26)7-24)17-12-3-2-10(25)5-14(12)22-19(17)23-15/h2-3,5-6,9,11,24-27H,4,7-8H2,1H3,(H,22,23)/t9-,11-/m0/s1