InChI=1S/C21H20O8/c1-29-12-4-2-3-10-14(12)20(27)16-15(18(10)25)19(26)11-7-21(28,13(23)8-22)6-5-9(11)17(16)24/h2-4,13,22-24,26,28H,5-8H2,1H3/t13?,21-/m1/s1