The addition of ethylhydrazine to α,β- and β,γ-unsaturated ketones: a quantum-chemical modeling

• Published in: Journal of physics. Conference series Vol. 1847; no. 1; p. 12052
• Main Authors: Gnatovsky, G R, Orel, V B, Vitkovskaya, N M
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.03.2021
• Subjects: Carbonyl groups; Carbonyls; Hydrazones; Ketones; Physics; Quantum chemistry; Water chemistry
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/1847/1/012052

Abstract The reactivity of α,β- and β,γ-unsaturated ketones with respect to the nucleophilic attack by ethylhydrazine in one of the key stages of the formation of 4,5-dihydropyrazole has been studied. It is shown that the addition of the terminal nitrogen atom of ethylhydrazine to the carbonyl group of β,γ- and α,γ-unsaturated ketones with the formation of β,γ- and α,β-unsaturated hydrazones is energetically preferable with the participation of two water molecules. At the same time, the addition of the internal nitrogen of ethylhydrazine to the double C=C bond of the α,β-unsaturated ketone (which is preferable in the presence of one water molecule) to give β-ethylhydrazinyl ketone occurs with a lower activation barrier and is thermodynamically more favorable than the addition to the C=O bond.