InChI=1S/C19H18O7S/c1-12(2)3-7-15-9-13(6-8-16(15)20)4-5-14-10-17(21)19(18(22)11-14)26-27(23,24)25/h3-11,20-22H,1H2,2H3,(H,23,24,25)/b5-4+,7-3+