InChI=1S/C20H20O10S/c1-27-16-9-12(4-5-15(16)21)19-14(10-29-31(24,25)26)13-7-11(3-6-18(22)23)8-17(28-2)20(13)30-19/h3-9,14,19,21H,10H2,1-2H3,(H,22,23)(H,24,25,26)/b6-3+