Hydrazine Derivatives of β-Dicarbonyl Compounds, Part I. Studies on Some Benzoylacetaldehyde Aroylhydrazones

Abstract

Abstract A series of benzoylacetaldehyde benzoylhydrazones were prepared and characterised. Their UV, IR, and 1H NMR spectra suggest the enol-imine structure rather than the keto-imine form of analogous Schiff bases. The pKa values of these aroylhydrazones were also measured and correlated with the Hammet substitution constants. Attempted cyclizations of these open-chain aroylhydrazones afforded the corresponding 5-hydroxy-2-pyrazoline compounds rather than the expected pyrazoles.