InChI=1S/C18H18N2O4/c1-9-12(5-6-17(22)23)10(2)19-15(9)8-14-13-4-3-11(21)7-16(13)20-18(14)24/h3-4,7-8,19,21H,5-6H2,1-2H3,(H,20,24)(H,22,23)/b14-8-