InChI=1S/C25H28O4/c1-16(2)6-5-7-17(3)8-11-21-22(13-20(27)15-24(21)28-4)25-12-18-9-10-19(26)14-23(18)29-25/h6,8-10,12-15,26-27H,5,7,11H2,1-4H3/b17-8+