InChI=1S/C18H20N2O8/c1-7(21)20-5-4-9-10-6-8(2-3-11(10)19-16(9)20)27-18-14(24)12(22)13(23)15(28-18)17(25)26/h2-3,6,12-15,18-19,22-24H,4-5H2,1H3,(H,25,26)