InChI=1S/C18H20O6S/c1-2-17(13-3-7-15(20)8-4-13)18(11-12-19)14-5-9-16(10-6-14)24-25(21,22)23/h3-10,19-20H,2,11-12H2,1H3,(H,21,22,23)/b18-17-