InChI=1S/C19H20O7S/c1-11(2)3-8-15-16(20)9-13(10-17(15)21)19-18(25-19)12-4-6-14(7-5-12)26-27(22,23)24/h3-11,18-21H,1-2H3,(H,22,23,24)/b8-3+