InChI=1S/C20H24O7/c1-5-11(2)18(23)27-16-9-20(4,25)7-6-14(22)13(10-21)8-15-17(16)12(3)19(24)26-15/h5-8,15-17,21,25H,3,9-10H2,1-2,4H3/b7-6-,11-5+,13-8-