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