InChI=1S/C21H20O9/c22-8-17-18(26)19(27)20(28)21(30-17)12-5-11-13(24)6-15(29-16(11)7-14(12)25)9-1-3-10(23)4-2-9/h1-7,17-23,25-28H,8H2