InChI=1S/C18H23NO4/c1-19-13-5-6-14(19)11-15(10-13)23-18(21)8-4-12-3-7-16(20)17(9-12)22-2/h3-4,7-9,13-15,20H,5-6,10-11H2,1-2H3/b8-4+/t13-,14+,15?