InChI=1S/C20H16O3/c21-16-9-14-13-7-6-11-3-1-2-10-4-5-12(18(13)17(10)11)8-15(14)19(22)20(16)23/h1-8,16,19-23H,9H2/t16-,19-,20-/m1/s1