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RING-CHAIN TAUTOMERISM OF 3-UNSUBSTITUTED TRIFLUOROMETHYL-CONTAINING N-ACYL-5-HYDROXY-2-PYRAZOLINES

В. В. Пакальнис, А. В. Зеров, С. И. Якимович, В. В. Алексеев
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Abstract


Reaction of the hydrazides of aromatic and pyridine-3(4)-carboxylic acids with 4‑ethoxy-1,1,1-tri-fluorobut-3-en-2-one leads to the formation of derivatives having a 5-hydroxy-2-pyrazoline structure. In solution in DMSO-d6 they are capable of exhibiting ring-chain equilibrium involving the 5-hydroxy-2-pyrazoline and enehydrazine tautomers. The latter form is represented by a mixture of Z- and E‑isomers with a significant preponderance of the latter. The product from the reaction of 4‑aminobenzohydrazide with 4-ethoxy-1,1,1-trifluorobut-3-en-2-one in a ratio of 1:2 has a structure containing 5-hydroxy-2-pyrazoline and enamine fragments.

How to Cite
Pakal'nis, V. V.; Zerov, A. V.; Yakimovich, S. I.; Alekseev, V. V. Chem. Heterocycl. Compd. 2014, 50, 1107. [Khim. Geterotsikl. Soedin. 2014, 1201.]

For this article in the English edition see DOI 10.1007/s10593-014-1570-8


Keywords


enamino ketones; 4-ethoxy-1,1,1-trifluorobut-3-en-2-one; hydrazides of aromatic acids; hydrazides of pyridinecarboxylic acids; 5-hydroxy-2-pyrazolines; ring-chain tautomerism

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