InChI=1S/C17H21NO3/c1-21-16-13-14(9-10-15(16)19)7-3-4-8-17(20)18-11-5-2-6-12-18/h3-4,7-10,13,19H,2,5-6,11-12H2,1H3/b7-3-,8-4+