InChI=1S/C21H20O12/c1-6-14(26)17(29)18(30)21(31-6)33-20-16(28)13-9(23)4-8(22)5-12(13)32-19(20)7-2-10(24)15(27)11(25)3-7/h2-6,14,17-18,21-27,29-30H,1H3