InChI=1S/C20H20O6/c1-22-17-6-11(2-4-15(17)21)19-13-8-24-20(14(13)9-23-19)12-3-5-16-18(7-12)26-10-25-16/h2-7,13-14,19-21H,8-10H2,1H3