InChI=1S/C20H18O6/c1-22-15-7-12-14(8-16(15)23-2)25-9-17-18(12)19(21)11-3-4-13-10(5-6-24-13)20(11)26-17/h3-4,7-8,17-18H,5-6,9H2,1-2H3/t17-,18+/m1/s1