InChI=1S/C22H26N2O4/c25-19-9-3-17(4-10-19)7-13-21(27)23-15-1-2-16-24-22(28)14-8-18-5-11-20(26)12-6-18/h3-7,9-13,25-26H,1-2,8,14-16H2,(H,23,27)(H,24,28)/b13-7+