Cycloacylation of N‐Phenyl‐3‐oxobutanethioamide with 3‐Aryl‐2‐propenoyl Chlorides.

Britsun, V. N.; Borisevich, A. N.; Samoilenko, L. S.; Lozinskii, M. O.

doi:10.1002/chin.200539133

Cited by 3 publications

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“…We note that the appearance of new methods [67] and the improvement of existing methods [3,[68][69][70] for the synthesis of 3-oxopropanethioamides have prompted further study of the heterocyclization of these thioamides.…”

Section: Heterocyclization Of 3-oxo-3-r-propanethioamides (R = Alk Ar)mentioning

confidence: 99%

“…Possible reasons for the chemoselectivity of the processes were considered in [79]. In the presence of potassium carbonate they undergo recyclization to the potassium salts of 4-acyl-5-mercapto-1-phenyl-2,3-dihydro-1H-pyrrole-2,3-dione 157 [81]. In all probability the reason for the recyclization is the lability of the S-C=O bond.…”

Section: [3+3] Cyclocondensation Of 3-oxopropanethioamides With 13-dmentioning

confidence: 99%

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Heterocyclization of thioamides containing an active methylene group (review)

Britsun

Esipenko

Lozinskii

2008

Chem Heterocycl Comp

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Data from the last six years on the heterocyclization of thioamides containing an active methylene group are analyzed and classified.At the present time there has been a considerable increase in the number of publications on the chemistry of thioamides, and this is explained by the value of the compounds as initial reagents for further transformations and particularly for the synthesis of various sulfur-and nitrogen-containing heterocycles [1][2][3][4][5][6][7][8]. The enormous practical significant of the latter is common knowledge -they have found application as drugs, pesticides, dyes, and preservatives.Thioamides with an active methylene group are attractive synthesis units for the production of heterocycles. These polyfunctional compounds can be represented by the formula R 3 -CH 2 CS-NR 1 R 2 (where R 1 , R 2 = H, Alk, Ar; R 3 is an electron-withdrawing group such as CN, AlkCO, ArCO, (AlkO) 2 PO, AlkSO 2 , ArSO 2 , NO 2 ). The presence of another reaction center (the methylene group) makes it possible to use them as N-С-С and S-C-C components for various condensations [1][2][3][4][5][6][7][8]. A special feature of such substrates is the ability to react both with dinucleophilic and with dielectrophilic and dipolar reagents. As a rule the products of these heterocyclizations contain functional groups, which makes it possible to achieve their modification or annelation. Such characteristics of thioamides with an active methylene group substantially increase their synthetic potential and extend the range of accessible heterosystems, while the use of modern physical methods of investigation (X-ray crystallographic analysis and 1D and 2D NMR spectroscopy) makes it possible to establish the structure of the obtained compounds unambiguously. The presence of biological activity in the products of these transformations also attracts investigators to this subject [5][6][7][8].The reason for the appearance of this review was the increasing need for generalization and classification of new information on the heterocyclization of such thioamides that had not been included in previous reviews [2][3][4][5] and also to define the trends in the study of these processes. Since one of the most important reports in this field is the review [1] we undertook an analysis of the literature that has appeared in the last six years.

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Section: Heterocyclization Of 3-oxo-3-r-propanethioamides (R = Alk Ar)mentioning

confidence: 99%

Section: [3+3] Cyclocondensation Of 3-oxopropanethioamides With 13-dmentioning

confidence: 99%

Heterocyclization of thioamides containing an active methylene group (review)

Britsun

Esipenko

Lozinskii

2008

Chem Heterocycl Comp

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“….1 ppm in the 13 C NMR spectrum (Table 2, compounds 4b,9b and the spectroscopic data in the study [13]). The 13 C NMR spectrum of compound 15a does not show signals in the region but shows a signal for an sp 3 -hybridized C-N carbon [14] with a chemical shift of 88.8 ppm.…”

Section: ' 3"mentioning

confidence: 99%

Synthesis and reactions of 1-R-3-benzoyl-5-ethoxycarbonyl-6-oxo-1,2,3,6-tetrahydropyridine-2-thiones

Britsun

Esipenko

Chernega

et al. 2007

Chem Heterocycl Comp

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Keywords: 1-R-3-benzoyl-5-ethoxycarbonyl-6-oxo-1,2,3,6-tetrahydropyridine-2-thiones, diethyl ethoxymethylenemalonate, 6-ethoxycarbonyl-2-imino-8-methyl-4-phenyl-1,2,7,8-tetrahydropyrido[2,3-d]-pyrimidin-7-one, 5-ethoxycarbonyl-7-methy-3-phenyl-6,7-dihydroisoxazolo[3,4-b]pyridine-6-one, N-R-3-oxo-3-phenylpropanethioamides, 9-R-7-ethoxycarbonyl-5-phenyl-8,9-dihydropyrido[2,3-d][1,2,4]triazolo-[1,5-a]pyrimidin-8-ones, X-ray structural analysis, cycloacylation.The cycloacylation of thioamides by unsaturated carboxylic acid derivatives is a convenient and practical method for the synthesis of sulfur containing azoles and azines [1][2][3][4][5].One of these reagents is diethyl ethoxymethylenemalonate, the ethoxy group of which has good nucleofuge properties. None the less, there are only two studies in which the cyclocondensation of this compound with thioamides is discussed [6,7]. It is likely that the low interest of investigators in this area of reactions is explained by the fact that the reaction is carried out under forcing conditions [7] and forms two [7] or three products [6].The aim of this work was the discovery of conditions for the cycloacylation of the N-R-3-oxo-3-phenylpropanethioamides 1a,b by diethyl ethoxymethylenemalonate 2 and the exploitation of the synthetic potential of the products obtained.It was found that the N-R-3-oxo-3-phenylpropanethioamides 1a,b condense with diethyl ethoxymethylenemalonate 2 in the presence of sodium ethylate. The reaction occurs selectively and its products are the 1-R-3-benzoyl-5-ethoxycarbonyl-6-oxo-1,2,3,6-tetrahydropyridine-2-thiones 3a,b.In all likelihood the high selectivity of the process is explained by the high CH-acidity of the thioamides 1a,b [8] when compared with the N-aryl-2-thiocarbamoylacetamides. The latter react with diethyl ethoxymethylenemalonate non selectively to give three products [6].

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“…In our paper [4] it was shown that the ratio of the keto and enol forms of 3-oxo-3-R 1 -N-R 2 -propanethioamides depends not only on the structure of the 3-oxo-3-R 1 -N-R 2 -propanethioamides but also on the nature (polarity) of the solvent. However, the existence of the enethiol conformations was not proved either by 1 H NMR spectroscopy [3] or by IR spectroscopy [2][3][4].It should be noted that 3-oxopropanethioamides, on the one hand, are convenient models for the study of prototropic tautomerism on account of their asymmetric structure but, on the other, there are experimental difficulties in determining the contributions from each tautomeric form. In addition, investigation of the tautomeric transformations of 3-oxo-3-R 1 -N-R 2 -propanethioamides is complicated by the presence of Z/E isomerism, which arises as a result of retarded 284 0040-5760/05/4105-0284…”

mentioning

confidence: 95%

“…The enol forms of 3-oxo-3-R 1 -N-R 2 -propanethioamides exist as two conformers (E 1 and E 2 ), the presence of which was demonstrated by low-temperature (-60°C) 1 H NMR spectroscopy [3]. In our paper [4] it was shown that the ratio of the keto and enol forms of 3-oxo-3-R 1 -N-R 2 -propanethioamides depends not only on the structure of the 3-oxo-3-R 1 -N-R 2 -propanethioamides but also on the nature (polarity) of the solvent. However, the existence of the enethiol conformations was not proved either by 1 H NMR spectroscopy [3] or by IR spectroscopy [2][3][4].…”

mentioning

confidence: 95%

Quantum-Chemical Investigation of Keto-enol-enethiol Tautomerism in 3-oxo-3-R1-N-R2-propanethioamides

2005

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The keto-enol-enethiol tautomerism in 3-oxo-3-R 1 -N-R 2 -propanethioamides under vacuum and in acetone was studied in terms of density functional theory. It was established that the equilibrium depends on the structure of the 3-oxo-3-R 1 -N-R 2 -propanethioamides and on the nature of the solvent, but the most stable form is as a rule the keto form stabilized by an intramolecular hydrogen bond.Key words: 3-oxo-3-R 1 -N-R 2 -propanethioamides, keto-enol-enethiol tautomerism, quantum-chemical calculations, density functional theory.Like 1,3-thioxocarbonyl compounds, 3-oxo-3-R 1 -N-R 2 -propanethioamides are susceptible to the formation of intramolecular hydrogen bonds, as a result of which they can exist in ketone, enol, and enethiol forms, which are in dynamic equilibrium with each other. Unlike the keto-enol-enethiol tautomerism of 1,3-thioxo ketones, which have been studied in tens of papers while the results were summarized in the review [1], the keto-enol-enethiol tautomerism of 3-oxo-3-R 1 -N-R 2 -propanethioamides has only been discussed in [2][3][4]. In these papers the tautomeric equilibrium of 3-oxo-3-R 1 -N-R 2 -propanethioamides was studied by 1 H NMR and IR spectroscopy. In [3] the authors suggested that 3-oxo-propanethioamides can be present in solutions in the keto (K 1-3 ), enol (E 1-2 ), and enethiol (T 1-2 ) forms in dynamic equilibrium. These investigators established by 1 H NMR spectroscopy that the dominant form for 3-oxo-3-R 1 -N-R 2 -propanethioamides (R 1 = CH 3 , R 2 = Ar) in deuterochloroform solution is the keto form, in which the K 1 tautomer makes the largest contribution. The enol forms of 3-oxo-3-R 1 -N-R 2 -propanethioamides exist as two conformers (E 1 and E 2 ), the presence of which was demonstrated by low-temperature (-60°C) 1 H NMR spectroscopy [3]. In our paper [4] it was shown that the ratio of the keto and enol forms of 3-oxo-3-R 1 -N-R 2 -propanethioamides depends not only on the structure of the 3-oxo-3-R 1 -N-R 2 -propanethioamides but also on the nature (polarity) of the solvent. However, the existence of the enethiol conformations was not proved either by 1 H NMR spectroscopy [3] or by IR spectroscopy [2][3][4].It should be noted that 3-oxopropanethioamides, on the one hand, are convenient models for the study of prototropic tautomerism on account of their asymmetric structure but, on the other, there are experimental difficulties in determining the contributions from each tautomeric form. In addition, investigation of the tautomeric transformations of 3-oxo-3-R 1 -N-R 2 -propanethioamides is complicated by the presence of Z/E isomerism, which arises as a result of retarded 284 0040-5760/05/4105-0284

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Cycloacylation of N‐Phenyl‐3‐oxobutanethioamide with 3‐Aryl‐2‐propenoyl Chlorides.

Abstract: Chlorides. -The cycloacylation of thioamide (I) with 3-aryl-2-propenoyl chlorides (II) affords thiooxopiperidinones (III) along with minor amounts of either thiopyranones (IV) or thiazinone (V). -(BRITSUN, V. N.; BORISEVICH, A. N.; SAMOILENKO, L. S.; LOZINSKII, M. O.; Russ.

Cited by 3 publications

References 1 publication

Heterocyclization of thioamides containing an active methylene group (review)

Heterocyclization of thioamides containing an active methylene group (review)

Synthesis and reactions of 1-R-3-benzoyl-5-ethoxycarbonyl-6-oxo-1,2,3,6-tetrahydropyridine-2-thiones

Quantum-Chemical Investigation of Keto-enol-enethiol Tautomerism in 3-oxo-3-R1-N-R2-propanethioamides

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