InChI=1S/C20H22N2O4/c1-21(15-3-2-4-20(23)24)18-11-7-16(8-12-18)5-6-17-9-13-19(14-10-17)22(25)26/h5-14H,2-4,15H2,1H3,(H,23,24)/b6-5+