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

Abstract

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

The Uses of Acetylacetone to Synthesize Pyridin-2- One Derivatives

“…Thus, the 1 H NMR spectrum of compound 5 showed the presence of four singlets at δ 1.61, 1.74, 2.44 and 2.62 ppm corresponding to the presence of four CH 3 groups. Also, the presence of signal at δ 5.35 ppm for C-H proton of the acetylacetone moiety and 11.54 (OH, D 2 O exchangeable) ppm supported that the condensation product 5 exist in the enolimine structure 5a (23) . Moreover, the electronic spectrum of compound 5 was recorded in MeOH, MeOH\H 2 SO 4 (0.1 M) and MeOH\NaOCH 3 (0.1M) ( Fig.…”

“…Condensation of compound 2 with acetylacetone afforded compound 5 which could be represented by any of the three possible tautomeric forms 5a, 5b or 5c (22,23) (Scheme 2). The structure of compound 5 was confirmed through the study of its spectral data and elemental analysis.…”

“…The 1 H NMR spectrum of 7b (as an example) showed the presence of two methyl signals at δ 2.11 and 2.42 ppm, together with multiplet at δ 7.21-7.64 ppm corresponding to the ten aromatic protons. The singlet at δ 7.90 ppm may be attributed to the OH proton of the enol-imine form 7b (R=CH 3 ), a behavior often characterizing such systems (23) . At the time being, 13 C NMR spectrum revealed δ: 19.8, 20.1 (2CH 3 ), 119.3 (CN), 162.9 (C=N), 173.1, 179.1 (2CO).…”

Diorganotin(IV) complexes with 2-furancarboxylic acid hydrazone derivative of benzoylacetone: Synthesis, X-ray structure, antibacterial activity, DNA cleavage and molecular docking

“…Rateb et al reported that the initial product of the condensation of benzoyl acetone and aroyl hydrazones is predominantly the enolimino form rather than the ketoenamine form and the former on cyclization gives a 5-hydroxypyrazoline derivative which may exhibit ring-chain tautomerism in solution [32]. Figure 1 show the synthesized acylhydrazone in cyclic and several chain tautomeric forms.…”