InChI=1S/C21H28O9/c1-2-3-9-14(23)10-6-7-12-15(11-5-4-8-13-22)29-21-18(26)16(24)17(25)19(30-21)20(27)28/h1,6,10,13-19,21,23-26H,4-5,7-8,11-12H2,(H,27,28)/b10-6+