InChI=1S/C20H22O11S/c21-9-15-19(31-32(27,28)29)17(25)18(26)20(30-15)16-11(7-13(23)8-14(16)24)4-1-10-2-5-12(22)6-3-10/h1-8,15,17-26H,9H2,(H,27,28,29)/b4-1+