InChI=1S/C21H21N3O4/c1-4-20(2,3)16-12(11-7-5-6-8-13(11)22-16)9-14-18(25)24-10-15-17(28-15)21(24,27)19(26)23-14/h4-9,15,17,22,27H,1,10H2,2-3H3,(H,23,26)/b14-9-