InChI=1/C21H22O6/c1-12(2)17(24)10-15-18(25)11-19(27-3)20(21(15)26)16(23)9-6-13-4-7-14(22)8-5-13/h4-9,11,17,22,24-26H,1,10H2,2-3H3/b9-6+