InChI=1S/C21H20O8S/c1-21(2)11-10-15-18(28-21)9-6-13(20(15)27-3)4-7-16(22)14-5-8-17(23)19(12-14)29-30(24,25)26/h4-12,23H,1-3H3,(H,24,25,26)