InChI=1S/C21H18O13S/c1-7-17(25)19(27)20(28)21(32-7)16-11(24)6-14-15(18(16)26)10(23)5-12(33-14)8-2-3-9(22)13(4-8)34-35(29,30)31/h2-7,19-22,24,26-28H,1H3,(H,29,30,31)