InChI=1S/C20H20O6/c21-8-15-14(5-12-1-3-16-18(6-12)25-10-23-16)9-22-20(15)13-2-4-17-19(7-13)26-11-24-17/h1-4,6-7,14-15,20-21H,5,8-11H2