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

Bozhenkov, G. V.; Savosik, V. A.; Ларина, Л. И.; Клыба, Л. В.; Zhanchipova, E. R.; Мирскова, А. Н.; Levkovskaya, G. G.

doi:10.1134/s1070428008070129

Cited by 11 publications

(15 citation statements)

References 4 publications

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“…It was shown that the reactions involving 2-dimethylamino-substituted aryl, hetaryl, and dimethoxymethylvinyl ketones afforded only 1-tert-butyl-5-aryl(hetaryl)(formyl)-substituted pyrazoles (NMR and XRD data). These results are in agreement with the data of [33,34,38] where has been reported on the aryl 2-chlorovinyl ketones to react with alkylhydrazines and also with arylhydrazines giving only 1,3-disubstituted isomers. Yet in the reaction of hexyl (2-dimethylaminovinyl) ketone with tertbutylhydrazine under the same conditions a mixture formed of 1,5-and 1,3-isomers in the ratio 7 : 1.…”

Section: Methodssupporting

confidence: 95%

“…We showed in this study that under the conditions of the regioselective synthesis of 1,3-dialkylpyrazoles from alkyl 2-chlorovinyl ketones and unsymmetrical dialkylhydrazines [32,33] and of a mixture of isomeric 1,3-and 1,5-dialkylpyrazoles from alkyl chlorovinyl ketones and alkylhydrazines [34] the reactions of alkyl, haloalkyl 2-chlorovinyl ketones with tert-butylhydrazine also led to the formation of a mixture of 1,3-and 1,5-isomers of 2 and 3 dialkylpyrazoles (see the Table, Scheme 1). 1,5-Isomers 3 are evidently less feasible thermodynamically than the 1,3-substituted analogs 2.…”

Section: Methodsmentioning

confidence: 98%

“…Considering 1 Н NMR spectra it should be first of all mentioned that introducing the tert-butyl group in the position 1 of pyrazoles 2a-2e and 3a-3e significantly affects the position of the signals from the protons of the heterocycle as compared with the corresponding signals in the spectra of the other 1,3-and 1,5-dialkylpyrazoles [33,34]. For instance, we formerly observed that in 1,3-and 1,5-dialkylpyrazoles the positions of Н 4 signals in the 1 Н NMR spectra practically coincided (∆δ ≈ 0.01 ppm), and the signals of Н 3 protons appeared downfield with respect to those of Н 5 protons [16] (see the figure).…”

Section: Methodsmentioning

confidence: 99%

“…The probe of 1 µL volume was admitted at a split ratio 1 : 2. Initial 2-chlorovinyl ketones 1a-1e, among them previously unknown ketone 1e, were obtained from the chlorides of the respective acids and acetylene at the catalysis with anhydrous aluminum chloride [31,33,34,39]. Propyl 2,2-dichlorovinyl ketone 6 was synthesized from butyroyl chloride and 1,1-dichloroethylene by procedure [43].…”

Section: Mass Spectra Of Electron Impact Of Compounds 2-7mentioning

confidence: 99%

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Synthesis and structure of 1-tert-butyl-substituted 3(5)-alkylpyrazoles from 2-chlorovinyl ketones

et al. 2015

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Reactions of alkyl, halomethyl 2-chlorovinyl ketones with tert-butylhydrazine in the presence of triethylamine afford unsymmetrical 1-(tert-butyl)-3-and -5-disubstituted pyrazoles. The reaction direction is governed by the ketone ability of the nucleophilic substitution of chlorine and of the dehydrochlorination leading to acetylene ketones. 2-Chlorovinyl ketones react with tert-butylhydrazine along two routes giving mixtures of 1-(tert-butyl)-3-and -5-alkylpyrazoles. The content of 3-alkyl-1-(tert-butyl)pyrazole in the formed isomers mixture grows up to 73% with growing length of the alkyl chain of the ketone and up to 87 and 94% at introducing halogen atom in the alkyl fragment of the chloroenone.Pyrazole and its derivatives attract attention due to the widest range of their pharmacologic activity [1][2][3][4][5], versatile specific agrochemical properties [6][7][8][9]. The high interest in this class of heterocyclic compounds originates as well from their large potential in modern technologies of dyes in cosmetics, photography and production of fluorescent substances and stabilizers [1][2][3][4][5]. Compounds of the pyrazole series find application both in the large-scale and fine organic synthesis [1][2][3][4][5], in the supramolecular [10] and polymer chemistry [11, 12], as liquid crystls [13], ligands for metal complex catalysis [14][15][16], in designing complexes with uncommon magnetic properties [17,18].The practical utilization of pyrazoles and the extension of their application fields requires not only development of synthetic procedures for new pyrazole derivatives, but mainly the solution of an important task of working out directional procedures for preparation of individual isomers of unsymmetrically substituted pyrazoles. The analysis of the known approaches shows the especially promising application of haloenones as initial reagents for pyrazole synthesis [19][20][21][22][23], in particular, of their individual isomers. The systematic investigation of the reactivity of versatile haloenones [24][25][26][27][28][29] demonstrated that the reactions of 2,2-dihalovinyl ketones with unsymmetrical dialkylhydrazines, alkyl-, arylhydrazines under various condition resulted in the chemo-and regiospecific formation of 1-alkyl(aryl)-5-halo-3-alkyl(aryl)(haloalkyl)pyrazoles. Therewith the hydrazine character does not considerably affect the process direction.The preparation of 1,3-disubstituted pyrazoles with no halogen atoms in the ring from 2-chlorovinyl ketones is governed by the hydrazine structure. The regioselective synthesis of 1,3-disubstituted pyrazoles from 2-chlorovinyl ketones occurs at the use of 1,1-dialkyl-and arylhydrazines [29][30][31]. At the same time no formation of two isomers was observed in the reactions of 2-chlorovinyl ketones with hydrazines containing a long alkyl chain [32].In extension of the research on the development of syntheses of dialkyl-substituted pyrazoles we studied the reactions of a number of 2-chlorovinyl ketones with tert-butylhydrazine. The goal of the work consiste...

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Section: Methodssupporting

confidence: 95%

Section: Methodsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%

Section: Mass Spectra Of Electron Impact Of Compounds 2-7mentioning

confidence: 99%

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Synthesis and structure of 1-tert-butyl-substituted 3(5)-alkylpyrazoles from 2-chlorovinyl ketones

et al. 2015

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“…Reactions of 2-chlorovinyl alkyl ketones with dialkylhydrazines lead to 1,3-substituted pyrazoles, whereas alkylhydrazines give rise to mixtures of 1,3-and 1,5-dialkylpyrazoles [20]. We have found that bis(dichlorovinyl ketone) II reacts with benzylhydrazine and 1,1-dimethylhydrazine in a chemoselective fashion, yielding previously unknown bridged bis-pyrazoles, 1,4-bis(1-benzyl-5-chloro-1H-pyrazol-3-yl)butane (IV) and 1,4-bis-(5-chloro-1-methyl-1H-pyrazol-3-yl)butane (V), respectively, in up to 83% yield (Scheme 2).…”

Section: IIImentioning

confidence: 99%

Synthesis of α,ω-bis(pyrazol-3-yl)alkanes: I. 1,4-bis(1-methyl- and 1-benzyl-5-chloro-1H-pyrazol-3-yl)-butanes from 1,1,10,10-Tetrachlorodeca-1,9-diene-3,8-dione and 1,1-dimethyl- or benzylhydrazine

et al. 2011

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Synthesis of α,ω-Bis(pyrazol-3-yl)alkanes: I. 1,4-Bis(1-methyl-and 1-benzyl-5-chloro-1H-pyrazol-3-yl)-butanes from 1,1,10,10-Tetrachlorodeca-1,9-diene-3,8-dione and 1,1-Dimethyl-or Benzylhydrazine Abstract-First representatives of bis-2-chloro-and 2,2-dichlorovinyl ketones, 1,10-dichlorodeca-1,9-diene-3,8-dione and 1,1,10,10-tetrachlorodeca-1,9-diene-3,8-dione, were synthesized by reaction of hexanedioyl dichloride with acetylene and 1,1-dichloroethene, respectively, in the presence of AlCl 3 . 1,1,10,10-Tetrachlorodeca-1,9-diene-3,8-dione reacted with benzylhydrazine and 1,1-dimethylhydrazine to give 1,4-bis(1-benzyl-5-chloro-1H-pyrazol-3-yl)butane and 1,4-bis(5-chloro-1-methyl-1H-pyrazol-3-yl)butane, respectively.Organic compounds containing two and more pyrazole fragments attract considerable interest from both theoretical and practical viewpoints primarily due to the possibility of using them as ligands for the preparation of polynuclear complexes and coordination polymers possessing valuable properties [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Multitopic pyrazole-containing ligands are also used as sorbents and intermediate products for the synthesis of compounds exhibiting biological and catalytic activity, and they can be involved in self-assembly of supramolecular ensembles, etc. On the other hand, organic polypyrazole ligands were studied insufficiently because of their low accessibility; therefore, search for new synthetic approaches to such compounds remains an important problem [1-17].The most widely known are ensembles in which pyrazole ring is linked through the pyrrole-type nitrogen atom [1][2][3][4][5][6][7][8][9][10][11][12]. 4,4′-Bis-pyrazole systems are fairly accessible; they are synthesized by reactions of polyelectrophiles with pyrazoles, aldehydes, and ketones [13][14][15]. A number of 3(5)-methyl(ethyl)-substituted bis-pyrazoles bridged at the 5,5′(3,3′)-positions by alkanediyl, 1,4-methylenephenyl, and 1,4′-diphenyleneoxy(disulfido) spacers were obtained by reaction of the corresponding bis-β-diketones with hydrazine hydrate [16,17]. Thus chemoselective synthesis of 3,3′-bridged bis-pyrazoles attracts strong interest.We develop a novel approach to linearly bridged α,ω-bis(pyrazol-3-yl)alkanes via heterocyclization of difunctional halovinyl ketones. In the present communication we report on the synthesis of first representatives of difunctional 2,2-dichloro-and 2-chlorovinyl ketones, 1,1,10,10-tetrachlorodeca-1,9-diene-3,8-dione (II) and 1,10-dichlorodeca-1,9-diene-3,8-dione (III) by reactions of adipoyl chloride with 1,1-dichloroethene and acetylene, respectively, in the presence of aluminum chloride according to the procedure described in [18] (Scheme 1). The reactions were carried out in methylene chloride at -5 to 20°C (reaction time 8 h. Unlike known procedures for the synthesis of alkyl 2,2-dichlorovinyl ketones [18], dehydrochlorination of 1,1,1,10,10,10-hexachlorodecane-3,8-dione (I) was effected by treatment with triethylamine. The yields (unoptimized) of ketone...

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The Structure of N‐phenyl‐pyrazoles and Indazoles: Mononitro, Dinitro, and Trinitro Derivatives

Claramunt

María

Alkorta

et al. 2017

Journal of Heterocyclic Chem

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

Cited by 11 publications

References 4 publications

Synthesis and structure of 1-tert-butyl-substituted 3(5)-alkylpyrazoles from 2-chlorovinyl ketones

Synthesis and structure of 1-tert-butyl-substituted 3(5)-alkylpyrazoles from 2-chlorovinyl ketones

Synthesis of α,ω-bis(pyrazol-3-yl)alkanes: I. 1,4-bis(1-methyl- and 1-benzyl-5-chloro-1H-pyrazol-3-yl)-butanes from 1,1,10,10-Tetrachlorodeca-1,9-diene-3,8-dione and 1,1-dimethyl- or benzylhydrazine

The Structure of N‐phenyl‐pyrazoles and Indazoles: Mononitro, Dinitro, and Trinitro Derivatives

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