InChI=1S/C18H22O9/c19-12-13(20)15(16(22)23)27-18(14(12)21)25-8-4-3-7-11-9-5-1-2-6-10(9)17(24)26-11/h2,6-7,12-15,18-21H,1,3-5,8H2,(H,22,23)/b11-7+