Distinguishing Features of reactions of 2-chloro-and 2,2-dichloro(bromo)vinyl ketones with alkyl-and arylhydrazines

Autor:	Lyudmila I. Larina, Mirskova Anna N, Lyudmila V. Klyba, Galina G. Levkovskaya, E. R. Zhanchipova, G. V. Bozhenkov, V. A. Savosik
Rok vydání:	2008
Předmět:	chemistry.chemical_classification chemistry.chemical_compound Ketone 13c nmr spectroscopy Trifluoromethyl chemistry Organic Chemistry Hydrazine Organic chemistry Pyrazole Medicinal chemistry Phenylhydrazine Alkyl
Zdroj:	Russian Journal of Organic Chemistry. 44:1014-1023
ISSN:	1608-3393 1070-4280
DOI:	10.1134/s1070428008070129
Popis:	2-Chlorovinyl alkyl ketones react with alkylhydrazines to give mixtures of 1-R-3-R′- and 1-R-5-R′-pyrazoles: The 1-R-3-R′-pyrazoles form through the heterocyclization of 2-chlorovinyl ketone alkylhydrazones whereas in the heterocyclization into 1-R-5-R′-pyrazoles N1-alkyl-N2-(2-acylvinyl)hydrazines are involved. The regiospecific heterocyclization of 2-chloro-and 2,2-dichlorovinyl ketones with arylhydrazines and also of 2,2-dichloro(bromo)vinyl trifluoromethyl ketones with C alkylhydrazines into pyrazoles and 5-chloro(bromo)-pyrazoles proceeds through a stage of haloenones hydrazones formation. The study of the structure of the obtained 1-alkyl-3(5)-alkylpyrazoles by means of two-dimenaional 1H and 13C NMR spectroscopy and GC-MS method made it possible to assign the proton and carbon signals of isomeric pyrazoles and to establish the diagnostic ions for the pair of 1,3-and 1,5-isomers.
Databáze:	OpenAIRE
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