InChI=1S/C20H21NO4/c1-21-7-6-12-13-5-4-11-8-16(22)17(24-2)9-14(11)18(13)20(25-3)19(23)15(12)10-21/h4-5,8-9,22-23H,6-7,10H2,1-3H3