1100829-55-7Relevant academic research and scientific papers
Ratio of 1,3- and 1,5-dialkyl-substituted pyrazoles obtained from chlorovinyl alkyl ketones and alkylhydrazines, 3(5)-pyrazoles and alkyl bromides
Popov,Rudyakova,Larina,Kobelevskaya,Levkovskaya
, (2014)
Unsymmetrically substituted 1,3- and 1,5-dialkylpyrazoles and 1,3-dialkyl-5-chloropyrazoles were prepared. 2-Chlorovinyl ketones react with C1-C8-alkylhydrazines along two routes giving mixtures of 1-R′-3-R- and 1-R′-5-R-pyrazoles wi
Distinguishing features of reactions of 2-chloro- and 2,2-dichloro(bromo) vinyl ketones with alkyl- and arylhydrazines
Bozhenkov,Savosik,Larina,Klyba,Zhanchipova,Mirskova,Levkovskaya
experimental part, p. 1014 - 1023 (2009/07/05)
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-N 2-(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.
