InChI=1S/C18H18N2O7/c1-7-12-10(4-5-19-7)9-3-2-8(6-11(9)20-12)26-18-15(23)13(21)14(22)16(27-18)17(24)25/h2-6,13-16,18,20-23H,1H3,(H,24,25)