InChI=1S/C21H18O7S/c1-26-16-9-7-13(10-17(16)28-29(23,24)25)15-8-6-12-4-3-5-14-11-18(27-2)21(22)20(15)19(12)14/h3-10,18H,11H2,1-2H3,(H,23,24,25)