InChI=1S/C18H20O6S/c1-3-15(12-5-8-14(9-6-12)24-25(21,22)23)16(4-2)17-10-7-13(19)11-18(17)20/h5-11,19-20H,3-4H2,1-2H3,(H,21,22,23)/b16-15-