InChI=1S/C17H16N4O7S/c1-11-4-2-3-5-14(11)19-17(23)8-12(22)10-18-20-15-7-6-13(29(26,27)28)9-16(15)21(24)25/h2-7,9H,8,10H2,1H3,(H,19,23)(H,26,27,28)/b20-18+