InChI=1S/C20H27NO4/c1-20(2,23)14-21-19(22)10-8-6-4-3-5-7-9-16-11-12-17-18(13-16)25-15-24-17/h7-13,23H,3-6,14-15H2,1-2H3,(H,21,22)/b9-7+,10-8+