The title compound, C6H8N2O4, a new derivative of isoxazole, has been synthesized and structurally characterized. The crystal structure shows the mol-ecule to be almost planar (r.m.s. deviation for the non-hydrogen atoms = 0.029 Å), this conformation being supported by an intra-molecular N-H⋯O hydrogen bond. In the extended structure, the mol-ecules are linked by N-H⋯O hydrogen bonds into chains propagating along [010].
The asymmetric unit of the title compound, C9H15NO4, consists of a functionalized pyrrolidine ring having an envelope conformation, synthesized as an ethyl ester. The mol-ecule has three chiral centres and crystallized as a racemic mixture. In the crystal, mol-ecules are linked by pairwise O-H⋯O bonds, generating dimers with twofold rotational symmetry.