InChI=1S/C18H20N4O4/c1-4-21-16-15(17(25)22(5-2)18(21)26)20(3)14(19-16)9-7-11-6-8-12(23)13(24)10-11/h6-10,23-24H,4-5H2,1-3H3/b9-7+