InChI=1S/C20H28O7/c1-6-9(2)17(23)26-16-14-10(3)18(24)27-20(14,25)15(22)12-7-8-13(21)11(4)19(12,16)5/h6,11-13,15-16,21-22,25H,7-8H2,1-5H3/b9-6+