Eth­yl 4-chloro-3-oxo-2-(phenyl­hydrazono)butyrate

The title compound, C₁₂H₁₃ClN₂O₃, adopts a keto–hydrazo tautomeric form stabilized by an intra­molecular N—H...O hydrogen bond. The configuration around the C=N bond is trans. The dihedral angle between the aromatic ring and the aliphatic chain is 5.52 (9)°. Symmetry-related mol­ecules are linked via C—H...O hydrogen bonds to form chains along the b axis.