InChI=1S/C21H28O12/c22-8-11-14(24)16(26)18(28)20(31-11)30-9-12-15(25)17(27)19(29)21(32-12)33-13(23)7-6-10-4-2-1-3-5-10/h1-7,11-12,14-22,24-29H,8-9H2/b7-6+