InChI=1S/C18H18O6S/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/h3-11,19-20H,1-2H3,(H,21,22,23)/b15-3?,16-4-