InChI=1S/C20H18O8/c1-27-16-9-11(3-5-15(16)21)8-14(20(25)26)13-7-12(4-6-18(22)23)10-17(28-2)19(13)24/h3-10,21,24H,1-2H3,(H,22,23)(H,25,26)/b6-4-,14-8+