InChI=1S/C21H20O7/c1-9(22)21(27)7-6-10-12(8-21)19(25)15-16(17(10)23)20(26)14-11(18(15)24)4-3-5-13(14)28-2/h3-5,9,22-23,25,27H,6-8H2,1-2H3/t9?,21-/m1/s1