InChI=1S/C21H18O5/c1-21(2)4-3-11-5-13-16(7-15(11)26-21)22-9-14-12-6-18-19(24-10-23-18)8-17(12)25-20(13)14/h3-8,14,20H,9-10H2,1-2H3