374912-82-0Relevant articles and documents
TAUTOMERISM IN THE SERIES OF BENZOYLHYDRAZONES OF ALIPHATIC β-DICARBONYL COMPOUNDS
Yakimovich, S. I.,Nikolaev, V. N.,Blokhtina, S. A.
, p. 1247 - 1254 (2007/10/02)
It was shown by PMR spectroscopy that the benzoylhydrazones of aliphatic β-dicarbonyl compounds exist in solutions as tautomeric mixtures of the cyclic 5-hydroxypyrazoline and open forms.The latter are represented by the hydrazone or enehydrazine form or their combination, depending on the structure of the β-dicarbonyl component and the solvent.Increase in the size of the terminal substituent at the C=N bond displaces the equilibrium toward the cyclic 5-hydroxypyrazoline form, and the introduction of strong electron-withdrawing substituents at the C=N bond favors the hydrazone and cyclic forms.The benzoylhydrazones of symmetrical β-diketones have a cyclic 5-hydroxypyrazoline structure.
