InChI=1S/C20H20N2O7/c1-28-13-5-3-4-12(8-13)6-7-18(24)22-15-10-17(29-2)16(23)9-14(15)20(27)21-11-19(25)26/h3-10,23H,11H2,1-2H3,(H,21,27)(H,22,24)(H,25,26)