A Facile Transfer of Dicyano Methylene Group Between Arylidenemalononitrile and Aldehyde

Ahmed, Shahadat; Sarmah, Utpal; Longchar, Moanochet; Boruah, Romesh C.; Sandhu, Jagir S.

doi:10.1080/00397910008087379

Cited by 9 publications

(4 citation statements)

References 16 publications

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“…Steroidal β-formyl enamides ( 1a , b ) were prepared from 16-dehydropregnenolone oxime under the influence of Vilsmeier reagent in good yields . Conversion of cyclohexanone to 1-acetamido-1-cyclohexene 23 followed by Vilsmeier formylation under mild condition afforded 1-acetamido-2-formyl-1-cyclohexene ( 4 ) in 69% yield.…”

Section: Resultsmentioning

confidence: 99%

“…DMF was dried over CaH 2 , and POCl 3 was freshly distilled. Compounds 1a , b were prepared from 16-DPA oxime following our earlier procedure …”

Section: Methodsmentioning

confidence: 99%

“…It was anticipated that reaction of this β-formylenamide and POCl 3 would generate a highly reactive and electrophilic substrate that could behave as an electron-deficient 1-aza-1,3-diene in a [4 + 2] cycloaddition reaction. Recently we have reported the preparation of a novel class of steroidal β-formylenamide and conveniently employed it as potential intermediate for synthesis of 17,17-dichloro-16( E )-chloromethyleneandrost-5-enes19a and steroidal des-D diynes 19b. We foresee enormous scope for this functionality as a new substrate in the emerging field of enamides …”

Section: Indroductionmentioning

confidence: 99%

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A Convenient Preparation of N-Acyl-1-aza-1,3-diene from β-Formylenamide and Its Utility in Inverse Electron Demand Diels−Alder Reactions

et al. 2000

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IndroductionThe Diels-Alder reaction of 1-azadienes is a valuable methodology for synthesis of nitrogen heterocycles 1 bearing endocyclic enamine moieties that are key intermediates in the preparation of complicated heterocycles 2a and natural products. 2b The 4π participation of simple 1-azadienes is rarely observed in normal [4 + 2] cycloaddition reactions; however, this problem could be circumvented by introducing either electron-withdrawing 1,3 or electrondonating 4 substitutents onto the nitrogen. Fowler 2 and Boger 5 have shown that substitution of the azadiene nitrogen by a strongly electron-withdrawing N-acyl or N-sulfonyl group favors considerably the inverse electron demand Diels-Alder(IEDDA) reactivity of the desired azadienes. Nevertheless, enormous efforts have been made toward production of electron-deficient 1-aza-1,3-butadienes that enable 4π participation of R, -unsaturated imines in [4 + 2] cycloaddition reactions. These have included intramolecular [4 + 2] cycloaddition of in situ generated N-acyl-1-aza-1,3-butadienes by vacuum pyrolysis 6 and under thermal condition, 7 in situ generated o-quinomethide monoimines, 8 the HOMO diene controlled Diels-Alder reaction of 1-(dimethylamino)-1-aza-1,3-butadienes, 9 the Lewis acid catalyzed intramolecular [4 + 2] cycloaddition reaction of in situ generated 2[(tertbutyldimethylsilyl)oxy]-1-aza-1,3-butadienes, 10 and intermolecular [4 + 2] cycloaddition of N-sulfonyl-1-aza-1,3-butadienes. 11 Recently significant attention has been drawn 12 to the influence of a cyano group at C-2, together with different nitrogen substituents (COR, Ph, alkyl, OMe, SO 2 Ph), on the Diels-Alder reactivity of azadiene systems. Interestingly, literature reveals that C-2-alkyl substituted N-acyl-1-azadienes are rare compounds, although corresponding 2-alkyl-N-sulfonyl-1-azadienes have provided well-behaved dienophiles for [4 + 2] cycloaddition studies. 13 The Vilsmeier reagent, which is derived from N,Ndimethylformamide and phosphorus oxychloride, corresponds to a chloromethyleneiminium salt structure (I, R)Me, Scheme 1). The potential of carbon-carbon bondforming reactions of halomethylene iminium salts involving aromatic and acyclic or alicyclic nuclei has been extensively studied. 14 The Vilsmeier reactions of enamides were found to proceed by cyclization of intermediate II to give fused pyridoderivatives. 15 The ring closure of N-aryl-N-methylformamides to quinolines can also be effected by treatment of electrophilic iminium salt (I, R ) Ar) with enamine via "reverse Vilsmeier approach". 16 All of these examples include amine precursors in which an enolizable formyl or acyl group is directly linked to the nitrogen atom. Nevertheless, Ulrich et al. 17 reported that 3-(dimethylamino)-acrolein is a prototype vinyl homologue of dimethylformamide, which could be employed for preparation of R, -unsaturated imine III to incorporate an acrolein moiety to a suitable nucleophile. These results suggested that if properly substituted * Ph: 091-0376-370327. FAX: 091-0376-370011. Hesba...

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Section: Resultsmentioning

confidence: 99%

“…DMF was dried over CaH 2 , and POCl 3 was freshly distilled. Compounds 1a , b were prepared from 16-DPA oxime following our earlier procedure …”

Section: Methodsmentioning

confidence: 99%

Section: Indroductionmentioning

confidence: 99%

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A Convenient Preparation of N-Acyl-1-aza-1,3-diene from β-Formylenamide and Its Utility in Inverse Electron Demand Diels−Alder Reactions

et al. 2000

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“…The high first order hyperpolarizability values are desired attributes for non-linear optics and luminescent chromophores. The compounds 4a and 4b can be easily synthesized by Knoevenagel condensation reaction starting from p-tolylaldehyde; and active methylene like malononitrile and ethylcyanoacetate respectively, [50] the compound 4c was synthesized by the condensation of 2-cyanomethyl benzthiazole and 4-methylbenzaldehyde in absolute ethanol at reflux temperature for 4 h. Similarly, the compound 4d was synthesi zed by the condensation of 2-(1-p h e n y l e t h y l i d e n e ) m a l o n o n i t r i l e a n d 4 -methylbenzaldehyde in methanol at reflux temperature for 12 h. The dyes COS1-COS4 were synthesized using the intermediates 4a-4d and 7-(diethylamino)-2-oxo-2 Hchromene-3-carbaldehyde by Knoevenagel condensation reaction in methanol at reflux temperature for an appropriate time. Here, we have used dry methanol as a solvent and only piperidine as a catalyst for the said reaction to afford the target molecules in 56 to 62 % yield of the pure products.…”

Section: Chemistrymentioning

confidence: 99%

AIE Based Coumarin Chromophore - Evaluation and Correlation Between Solvatochromism and Solvent Polarity Parameters

Lanke

Sekar

2015

J Fluoresc

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A new class of red emitting extensively conjugated donor-π-acceptor type dyes bearing coumarin units have been synthesized by condensation of 7-(diethylamino)-2-oxo-2 H-chromene-3-carbaldehyde with different active methylenes. All the dyes are characterized by (1)H NMR, (13)C NMR and HRMS spectroscopy. The photophysical behaviour and the relation between structure and properties of the coumarin "push-pull" derivatives were investigated experimentally. The dyes exhibited positive solvatochromism and solvatofluorism in solution of varying polarity. These coumarin dyes show aggregation induced emission properties with red emitting fluorescence. They show absorption in the range of 501-528 and emission in the range of 547-630 nm. We evaluated photophysical properties of coumarin dyes using solvotochromism and solvent dependent shift in the emission wavelength. All the synthesized coumarin dyes COS1-COS4 are showing very good solvatochromic properties.

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ChemInform Abstract: A Facile Transfer of Dicyanomethylene Group Between Arylidenemalononitrile and Aldehyde.

et al. 2000

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A Facile Transfer of Dicyano Methylene Group Between Arylidenemalononitrile and Aldehyde

Cited by 9 publications

References 16 publications

A Convenient Preparation of N-Acyl-1-aza-1,3-diene from β-Formylenamide and Its Utility in Inverse Electron Demand Diels−Alder Reactions

A Convenient Preparation of N-Acyl-1-aza-1,3-diene from β-Formylenamide and Its Utility in Inverse Electron Demand Diels−Alder Reactions

AIE Based Coumarin Chromophore - Evaluation and Correlation Between Solvatochromism and Solvent Polarity Parameters

ChemInform Abstract: A Facile Transfer of Dicyanomethylene Group Between Arylidenemalononitrile and Aldehyde.

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