Ethyl 4-chloro-2-[(2-nitrophenyl)hydrazono]-3-oxobutyrate.

The title compound, C12H12N3O5, adopts a keto-hydrazo tautomeric form stabilized by intra­molecular hydrogen bonds. The aromatic ring and aliphatic chain, which adopt a trans configuration about the C=N double bond, are nearly coplanar, with a dihedral angle of 7.56 (1)° between them. The mol­ecules pack via weak inter­molecular C—H⋯O hydrogen bonds which, together with intra­molecular N—H⋯O bonds, form an S(6) S(6)[ R22(13)] S(6) S(6) motif. [ABSTRACT FROM AUTHOR]