[3+2]- Versus [4+2]-cycloaddition reactions of 3-methylsulfanyl-2-arylazo-3-(pyrrolidin-1-yl)acrylonitriles with N-substituted maleimides involving pyrrolidine-derived azomethine ylides

Deryabina, T. G.; Belskaia, Natalia P.; Кодесс, М. И.; Dehaen, Wim; Toppet, Suzanne; Бакулев, В. А.

doi:10.1016/j.tetlet.2005.12.130

Cited by 15 publications

(4 citation statements)

References 10 publications

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“…Under identical conditions as described above, [3 + 2] cycloaddition reaction of 265 as a masked 1,3-dipole with N -methyl- or N -phenylmaleimide as dipolarophile gives 266 in high to excellent yields (Scheme , 22 examples, 71–95% yields). − It was shown that dimethyl maleate and dimethylacetylene dicarboxylate were also effective dipolarophiles for the [3 + 2] cycloaddition with 265 as masked 1,3-dipole . However, under similar reaction conditions, none of the desired [3 + 2] adduct, such as 268 , could be obtained when 267 was used, indicating that the azo function is important, acting as a base to abstract an acidic α-proton adjacent to the iminium nitrogen of intermediate 262 for in situ generation of 263 as the 1,3-dipole.…”

Section: Annulation Reactionsmentioning

confidence: 99%

Chemistry of Ketene N,S-Acetals: An Overview

et al. 2016

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Push-pull alkenes, which bear electron-donating and -accepting group(s) at both termini of a C═C double bond, respectively, are of interest not only for their unique electronic properties but also for their importance as versatile building blocks in organic synthesis. In the world of ketene acetals having the push-pull alkene skeleton, ketene N,S-acetal is most likely the biggest family according to the number and types of these compounds. The first ketene N,S-acetal compound was reported in 1956. As a cyclic ketene N,S-acetal compound, nithiazine, the first lead structure of neonicotinoid insecticides, was reported in 1978. The characteristics of ketene N,S-acetals, which have the structural feature of ketene S,S-acetals and enaminones, make them versatile and easy to use, especially in cyclization and multicomponent reactions for the synthesis of various heterocyclic systems and related natural products. There has been an increasing wealth of information about the synthesis and synthetic applications of ketene N,S-acetals, especially, in recent years. This review provides comprehensive knowledge on the chemistry of ketene N,S-acetals.

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Section: Annulation Reactionsmentioning

confidence: 99%

Chemistry of Ketene N,S-Acetals: An Overview

et al. 2016

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“…In addition to the cycloaddition product, small amounts of the cyclization products 122 were also isolated. Similar cycloaddition reactions at the α-carbon atom of the amino group were demonstrated [88][89][90] for the azo analogs 125. It was shown by quantum-chemical calculations [89] that the rate-limiting step was proton transfer (with 14.9 kcal/mol energy barrier).…”

Section: -92%mentioning

confidence: 54%

tert-Amino effect: the Meth-Cohn and Reinhoudt reactions (Review)

Platonova

Глухарева

Zimovets

et al. 2013

Chem Heterocycl Comp

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The term "tert-amino effect" was proposed in 1972 [1] for the cyclization reactions of tertiary anilines containing various double bonds at the ortho position. Meth-Cohn and Suschitzky [1] referred to the first observation of the tert-amino effect by Pinnow in 1895 [2]. Many different examples of reactions involving the tert-amino effect have now accumulated, and it clearly is a convenient method for the synthesis of an impressive number of nitrogen-containing heterocycles that otherwise might be difficult to obtain. Reviews were published by Reinhoudt in 1990 [3] and by Meth-Cohn in 1996 [4] on heterocyclization reactions that take place by the mechanism of the tert-amino effect. Another review dedicated to 1,6-and 1,8-naphthiridine derivatives was published in 2003 by Quintela [5]. In the review [6] that we published in 2005, attention was focused on the use of such reactions for the synthesis of spiro compounds. In the review [7], published in 2006, the cyclization reactions of ortho-vinylanilines and their heterocyclic aza analogs were considered, and classification according to the method of ring formation was proposed.

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“…PTB 1 was obtained by condensation of the thioamide 4 [18a–c] with 2‐bromo‐1‐phenylpropan‐1‐one 5 . The side C5 Me‐group easily forms effective C‐electrophile center by bromination (Scheme 2).…”

Section: Resultsmentioning

confidence: 99%

Photocaging of Carboxylic Function Bearing Biomolecules by New Thiazole Derived Fluorophore

Gagarin,

Minin,

Shevyrin

et al. 2023

Chemistry A European J

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The design and synthesis of a new fluorophore containing an arylidene thiazole scaffold resulted in a compound with good photophysical characteristics. Furthermore, the thiazole C5‐methyl group was easily modified into specific functional groups (CH2Br and CH2OH) for the formation of a series of photocourier molecules containing model compounds (benzoic acids), as well as prodrugs, including salicylic acid, caffeic acid, and chlorambucil via a “benzyl” linker. Spectral characteristics (1Н, 13С NMR, and high‐resolution mass spectra) corresponded to the proposed structures. The photocourier molecules demonstrated absorption with high values of coefficient of molar extinction, exhibited contrasting green emission, and showed good dark stability. The mechanism of the photorelease was investigated through spectral analysis, HPLV‐HRMS, and supported by TD‐DFT calculations. The photoheterolysis and elimination of carboxylic acids were proved to occur in the excited state, yielding a carbocation as an intermediate moiety. The fluorophore structure provided stability to the carbocation through the delocalization of the positive charge via resonance structures. Viability assessment of Vero cells using the MTT‐test confirmed the weak cytotoxicity of prodrugs without irradiation and it increase upon UV‐light.

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[3+2]- Versus [4+2]-cycloaddition reactions of 3-methylsulfanyl-2-arylazo-3-(pyrrolidin-1-yl)acrylonitriles with N-substituted maleimides involving pyrrolidine-derived azomethine ylides

Cited by 15 publications

References 10 publications

Chemistry of Ketene N,S-Acetals: An Overview

Chemistry of Ketene N,S-Acetals: An Overview

tert-Amino effect: the Meth-Cohn and Reinhoudt reactions (Review)

Photocaging of Carboxylic Function Bearing Biomolecules by New Thiazole Derived Fluorophore

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