InChI=1S/C16H20N4O4S/c17-15(18)12-5-2-10(3-6-12)1-4-11-7-8-13(16(19)20)9-14(11)24-25(21,22)23/h1-8,13-14H,9,17-18H2,(H3,19,20)(H,21,22,23)/b11-4+