InChI=1S/C21H22O5/c1-21(2)19(24)12-16-18(25-3)11-9-15(20(16)26-21)17(23)10-6-13-4-7-14(22)8-5-13/h4-11,19,22,24H,12H2,1-3H3/b10-6+