InChI=1S/C14H10N2O5S2/c15-23(19,20)10-4-1-8(2-5-10)11-6-3-9(21-11)7-12-13(17)16-14(18)22-12/h1-7H,(H2,15,19,20)(H,16,17,18)/b12-7-