InChI=1S/C21H20O5/c1-21(2)19(24)17-16-15(25-20(17)26-21)11-9-13(18(16)23)14(22)10-8-12-6-4-3-5-7-12/h3-11,17,19-20,23-24H,1-2H3/b10-8+/t17-,19-,20+/m0/s1