InChI=1S/C18H12Cl2N2O4/c19-9-7-13(20)16-12(17(18(25)26)22-14(16)8-9)5-6-15(24)21-10-1-3-11(23)4-2-10/h1-8,22-23H,(H,21,24)(H,25,26)/b6-5+