InChI=1S/C21H22O10/c22-10-16-18(27)19(28)20(21(30-16)29-13-5-3-12(23)4-6-13)31-17(26)8-2-11-1-7-14(24)15(25)9-11/h1-9,16,18-25,27-28H,10H2/b8-2+