InChI=1S/C19H20N2O5/c1-12-8-9-15(19(23)24)16(10-12)26-11-13-6-4-5-7-14(13)17(21-25-3)18(22)20-2/h4-10H,11H2,1-3H3,(H,20,22)(H,23,24)/b21-17+