InChI=1S/C21H20O8/c1-9(2)5-13(24)16-12(8-22)18-20(17(25)19(16)27-4)29-21(26)15-10(3)6-11(23)7-14(15)28-18/h5-7,22-23,25H,8H2,1-4H3