InChI=1S/C26H28O4/c1-16(2)5-11-20-24(29)19-13-14-26(3,4)15-21(19)23(25(20)30)22(28)12-8-17-6-9-18(27)10-7-17/h5-10,12-14,27,29-30H,11,15H2,1-4H3/b12-8+