InChI=1S/C21H28O8/c1-2-3-12-15(13-10-8-6-4-5-7-9-11-14-22)28-21-18(25)16(23)17(24)19(29-21)20(26)27/h1,10,13-19,21,23-25H,4-9,11H2,(H,26,27)/b13-10+