InChI=1S/C18H18N2O8/c1-6-12-7(2-3-19-6)8-4-10(21)11(5-9(8)20-12)27-18-15(24)13(22)14(23)16(28-18)17(25)26/h2-5,13-16,18,20-24H,1H3,(H,25,26)