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Strakova, I. A.; Strakovs, A.; Петрова, М. В.

doi:10.1023/a:1016079221645

Chemistry of Heterocyclic Compounds

2002

DOI: 10.1023/a:1016079221645

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I. A. Strakova

A. Strakovs

М. В. Петрова

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Cited by 11 publications

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“…The reaction proceeds regioselectively. In every case one regioisomer is formed, as was shown previously for the reaction of 2-acetylcyclohexane-1,3-diones with phenylhydrazines [10][11][12][13]. It should be mentioned that the formation of fluoro-substituted indazolones 3a-j requires significantly more time than in the case of the unsubstituted derivatives.…”

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confidence: 53%

“…The structures of the synthesized compounds 2f,g, 3a-j, and 6a-j were confirmed by data of elemental analysis, IR, mass, and 1 H, 13 C, and 19 F NMR spectra (Tables 1, 2). Indazolones 3f,g and hydrazones 2f,g are readily distinguished spectrally.…”

mentioning

confidence: 67%

“…IR Spectra and 1 H,13 C, and19 F NMR Spectra of the Synthesized Compounds 3a-j, 6a-j 6Н, s, 2СН3); 1.15 (3Н, t, J = 7.5, СН3);…”

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confidence: 99%

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Regioselective synthesis of fluorine-containing indazolones from 2-acylcyclohexane-1,3-diones

Khlebnicova

Isakova

Лахвич

et al. 2008

Chem Heterocycl Comp

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New regioisomeric indazolones containing fluorine atoms in the aromatic ring have been synthesized in high yield by the interaction of 2-acylcyclohexane-1,3-diones, and of their enol methyl ethers, obtained by methylating the initial β,β′-triketones with dimethyl sulfate in the presence of calcined potassium carbonate, with 4-fluorophenylhydrazine hydrochloride and with pentafluorophenylhydrazine. The structures of the synthesized compounds were confirmed by data of IR and 1 H, 13 C, and 19 F NMR spectra.At the present time methods of synthesizing various fluorine-containing polyfunctional heterocyclic structures as medicinal preparations are being developed vigorously [1,2]. Indazoles are an important class of organic compounds, many of which possess anti-inflammatory, analgesic, antiviral, and other physiological activitities [3,4].The aim of the present work was to obtain new fluorine-containing indazolones from various 2-acylcyclohexane-1,3-diones.Thanks to their polyfunctionality and depending on the structure of the acyl side chain and the cyclic portion of the molecule the 2-acylcyclohexane-1,3-diones are widely applied in the synthesis of steroids, prostaglandins, antibiotics, and other biologically active substances [5][6][7][8]. Chemical conversions of 2-acylcyclohexane-1,3-diones existing in the enolic form may also affect such reaction centers as the exo-and endocyclic carbonyl groups, and also the methylene groups adjacent to them [9].With the aim of synthesizing new derivatives of indazolones containing a fluorine atom in position 4 of the benzene ring or a completely fluorinated benzene ring we studied the interaction of 2-acylcyclohexane-1,3-diones 1a-e and their methyl ethers with 4-fluorophenylhydrazine and pentafluorophenylhydrazine.The interaction of 2-acylcyclohexane-1,3-diones 1a-e with a small excess of an equimolar mixture of 4-fluorophenylhydrazine hydrochloride and sodium hydroxide in ethanol for 8 h at room temperature led in high yield to the products of heterocyclization, indazolones 3a-e. The intermediate hydrazones 2a-e were not isolated. _______ * Dedicated to Distinguished Scientist Academician A. A. Akhrem in his 95 th Year.

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confidence: 53%

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confidence: 67%

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Regioselective synthesis of fluorine-containing indazolones from 2-acylcyclohexane-1,3-diones

Khlebnicova

Isakova

Лахвич

et al. 2008

Chem Heterocycl Comp

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“…Among them agonists of estrogen receptors [1] and dopamine D3 receptors [2], HIV protease inhibitors [3], and new anti-inflammatory substances [4] have been discovered. In this connection in a continuation of researches on the synthesis of 4,5-bifunctional 6,7-dihydro-and 4,5,6,7-tetrahydroindazoles [5][6][7][8][9][10] we realized [3+2] cycloaddition reactions between 5-diazo-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazoles 1a-d and maleic anhydride.…”

mentioning

confidence: 96%

5-Diazo-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazoles in [3+2] cycloaddition reactions

Strakova

Strakovs

Петрова

et al. 2007

Chem Heterocycl Comp

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Keywords: dimethyl acetylenedicarboxylate, 1,3-and 2,3-substituted 5-diazo-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazoles, maleic anhydride, [3+2] cycloaddition.In the last ten years the range of indazole derivatives with valuable biological activity has increased substantially. Among them agonists of estrogen receptors [1] and dopamine D3 receptors [2], HIV protease inhibitors [3], and new anti-inflammatory substances [4] have been discovered. In this connection in a continuation of researches on the synthesis of 4,5-bifunctional 6,7-dihydro-and 4,5,6,7-tetrahydroindazoles [5-10] we realized [3+2] cycloaddition reactions between 5-diazo-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazoles 1a-d and maleic anhydride.The diazoindazoles 1a,b,d were obtained by the decomposition of the corresponding tosylhydrazones 2a,b,d in a water-ethanol solution of sodium hydroxide according to the procedure in [11,12] that we used earlier for the preparation of the diazoindazoles 1c and 3.

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“…In continuation of studies on the modification of hydrogenated indazoles and quinazolines, mainly in their carbocyclic structural fragment [1][2][3][4][5], we have turned to the synthesis of 3-aryl-4-oxo-4,5,6,7-tetrahydroindazoles. Two schemes are known for their synthesis.…”

mentioning

confidence: 99%

3-Aryl- and 2,3-Diaryl-4-oxo-4,5,6,7-tetrahydroindazoles. 1. Reactions of Phenyl- and Tosylhydrazones of Dimedone and Cyclohexane-1,3-dione with Substituted Benzaldehydes

Strakova

Strakovs

Петрова

2005

Chem Heterocycl Compd

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Keywords: 3-aryl-and 2,3-diaryl-4-oxo-4,5,6,7-tetrahydroindazoles, substituted benzaldehydes, phenyland tosylhydrazones of cyclohexane-1,3-diones.In continuation of studies on the modification of hydrogenated indazoles and quinazolines, mainly in their carbocyclic structural fragment [1-5], we have turned to the synthesis of 3-aryl-4-oxo-4,5,6,7-tetrahydroindazoles. Two schemes are known for their synthesis. One is the interaction of enehydrazines, obtained from cyclohexane-1,3-diones and benzenesulfonic acid hydrazide, with aromatic aldehydes [6], and the other is the interaction of 2-benzoylcyclohexane-1,3-diones with hydrazines [7]. 2,3-Diaryl-4-oxo-4,5,6,7-tetrahydroindazoles are obtained by the interaction of phenylhydrazones of cyclohexane-1,3-diones with aromatic aldehydes [8] and by the reaction of 2,3-diphenyl-1,3,4-oxadiazolium perchlorate with dimedone [9].We selected the reaction of 3-enehydrazino-2-cyclohexen-1-ones with aromatic aldehydes for the synthesis of 3-aryl-and 2,3-diaryl-4-oxo-4,5,6,7-tetrahydroindazoles [6,8]. Such a selection was made, in spite of the extremely large number of known 2-aroylcyclohexane-1,3-diones [10-13] many of which are herbicides, because of the simplicity of the synthesis and the availability of a wide selection of aldehydes.In the present work 16 new 2,3-diaryl-4-oxo-4,5,6,7-tetrahydroindazoles 6 were synthesized by the reaction of phenylhydrazones of dimedone 2,3A and cyclohexane-1,3-dione 2,3B with substituted benzaldehydes 4.It was shown previously [8] that on boiling the reactants in alcohol for 15 min pyrazolines of type 5 are formed predominantly with only a little of their dehydrogenation products 6. However the procedure for separating these compounds is complex, and in addition pyrazolines 5 are unstable. We selected more rigid reaction conditions, heating a solution of equimolar quantities of reactants in DMSO at 100°C for 3-4 h, which leads to the formation of compounds 6 exclusively (Table 1).

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Cited by 11 publications

References 2 publications

Regioselective synthesis of fluorine-containing indazolones from 2-acylcyclohexane-1,3-diones

Regioselective synthesis of fluorine-containing indazolones from 2-acylcyclohexane-1,3-diones

5-Diazo-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazoles in [3+2] cycloaddition reactions

3-Aryl- and 2,3-Diaryl-4-oxo-4,5,6,7-tetrahydroindazoles. 1. Reactions of Phenyl- and Tosylhydrazones of Dimedone and Cyclohexane-1,3-dione with Substituted Benzaldehydes

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