organic compounds
The title compounds, C11H10Cl2N2O4, are constitutional isomers which exhibit similar molecular geometry. The configuration about the N=C bond is E in both molecules. The same packing pattern was found in both structures. Hydrogen-bonded dimers, formed around the inversion centres via O-HO interactions of carboxyl groups are connected into infinite chains. The intramolecular hydrogen bond N—HCl observed only in the 2,5-dichlorophenyl derivative contributes to the planarity of the molecule.