Description:
The title compound, C14H12N2O4, is nearly planar with a dihedral angle between the aromatic rings of 1.41 (8)°. The phenolic O atom is deprotonated and the N atom of the azomethine unit carries the proton, thereby forming an intramolecular N—H...O hydrogen bond. In the crystal, the molecules form inversion dimers via pairwise O—H...O hydrogen bonds.