InChI=1S/C20H20O7/c1-25-16-9-12(4-5-15(16)22)19-14(10-21)13-7-11(3-6-18(23)24)8-17(26-2)20(13)27-19/h3-9,14,19,21-22H,10H2,1-2H3,(H,23,24)/b6-3+