InChI=1S/C18H31NO4/c1-4-6-7-8-14-13(9-10-15(14)20)11-16(21)19-17(18(22)23)12(3)5-2/h6-7,12-15,17,20H,4-5,8-11H2,1-3H3,(H,19,21)(H,22,23)/b7-6+