InChI=1S/C18H18N2O8/c21-6-11-12-9(3-4-19-11)8-2-1-7(5-10(8)20-12)27-18-15(24)13(22)14(23)16(28-18)17(25)26/h1-5,13-16,18,20-24H,6H2,(H,25,26)