InChI=1S/C21H28O11/c1-11(9-31-20-17(26)15(24)16(25)18(32-20)19(27)28)7-13(22)8-21(2,29)5-3-14(23)12-4-6-30-10-12/h4,6-7,10,15-18,20,24-26,29H,3,5,8-9H2,1-2H3,(H,27,28)/b11-7+