InChI=1S/C19H20O7S/c1-13(12-20)2-9-17-18(21)10-15(11-19(17)22)4-3-14-5-7-16(8-6-14)26-27(23,24)25/h2-11,13,20-22H,12H2,1H3,(H,23,24,25)/b4-3+,9-2+