InChI=1S/C20H20O5/c1-13(2)9-10-25-16-11-18(23)20(19(24)12-16)17(22)8-5-14-3-6-15(21)7-4-14/h3-9,11-12,21,23-24H,10H2,1-2H3/b8-5+