Synthesis of π-conjugated thiophenes starting from substituted 3-oxopropanenitriles via Gewald reaction

Puterová, Zita; Andicsová, Anita Eckstein; Végh, Dániel

doi:10.1016/j.tet.2008.09.032

Cited by 49 publications

(24 citation statements)

References 46 publications

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“…However, it is sure, that S 8 has to be activated to react with Knoevenagel-Cope product 9. Some authors report that the activation of sulfur and the following addition of sulfur on a methylene group is base-promoted [57][58][59] , others detail the electrochemical activation of the S 8 .…”

Section: Methodsmentioning

confidence: 99%

“…The most suitable base for the activation with sulfur and the subsequent sulfur addition morpholine has been proved. 59 The morpholine exhibits the best solubility of sulfur from the entire organic base used in Gewald reaction. Additionally, by mixing the morpholine with sulfur at 150 °C the morpholine polysufide (MPS) is formed, which structure is presumed to contain from 2 -5 sulfur atoms within two morpholine molecules.…”

Section: -62mentioning

confidence: 99%

“…While in some cases the ylidene dimerization is significant and the by-product is isolated in higher yield than the desired 2-aminothiophene derivative 58 , on other hand under suitable reaction conditions not only is the straightforward reaction favored, but also the recyclization of dimerized ylidene 14 to appropriate aminothiophene 7 occurs. 59 The dimer 14 preferably is formed in the less studied, so-called redesigned Gewald procedure which is suitable for preparation six-membered carbonitriles with a free amino group. 67 If the reaction is directed towards formation of derivatives 14, the anion generated from the α,β-unsaturated nitrile 9 undergoes first to base-promoted Michael addition which is followed by Thorpe cyclization of the adduct 13 to create cyclohexadiene system 14 (Scheme 10).…”

Section: Dimerization Vs Cyclizationmentioning

confidence: 99%

“…59 The synthesis of β-aryl or β-heteroaryl substituted 2-aminothiophenes 85 utilizing the Gewald reaction of substituted 3-oxopropanenitriles 83a-d and substituted acetonitriles 84a,b 57 as is presented on Scheme 24.…”

Section: Synthesis Of π-Conjugated Thiophenes Via Gewald Reactionmentioning

confidence: 99%

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Gewald reaction: synthesis, properties and applications of substituted 2-aminothiophenes

Puterová¹,

Krutošíková²,

Végh³

2010

Arkivoc

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168

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Chemistry of 2-aminothiophenes is arguably one of the most extensive and dynamic field of present-day thiophene research. Since 1961 when first report on the Gewald reaction was reported it became a universal method for synthesis of substituted 2-aminothiophenes and has gained prominence in recent times. The availability of reagents and the mild reaction conditions all contribute to the versatility of this reaction. This review summarizes the synthetic strategies for substituted 2-aminothiophenes. Consequently, details about the proposed mechanism of Gewald-like reactions and the wide scope of substituted 2-aminothiophenes for real life applications.

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Section: Methodsmentioning

confidence: 99%

Section: -62mentioning

confidence: 99%

Section: Dimerization Vs Cyclizationmentioning

confidence: 99%

Section: Synthesis Of π-Conjugated Thiophenes Via Gewald Reactionmentioning

confidence: 99%

See 2 more Smart Citations

Gewald reaction: synthesis, properties and applications of substituted 2-aminothiophenes

Puterová¹,

Krutošíková²,

Végh³

2010

Arkivoc

Self Cite

168

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“…2-Cyanoacetyl-1-methylpyrrole 1 was prepared using a modification of a published procedures 15 where only 1-methylpyrrole, cyanoacetic acid, and acetic anhydride were heated together. We could obtain X-ray crystal structure for this product ( Figure 1).…”

Section: Resultsmentioning

confidence: 99%

Studies with 3-oxoalkanenitriles: novel rearrangements observed while exploring the utility of 3-(1-methyl-2-pyrrolyl)-3-oxopropanenitrile as a precursor to pyrrole-substituted heterocyclic compounds

Al‐Matar¹,

Adam²,

Khalil³

et al. 2012

Arkivoc

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2-Cyanoacetyl-1-methylpyrrole 1 reacts with acetylacetone in glacial acetic acid in presence of ammonium acetate to yield a polysubstituted pyridine derivative 5. In contrast, ethyl acetoacetate reacts with 1 to yield a pyranone derivative 8, formed via a rearrangement process. Enaminonitrile 3, generated by reaction of 2-cyanoacetyl-1-methylpyrrole 1 with the dimethylformamide dimethylacetal (DMFDMA), undergoes condensation with malononitrile to yield a 2-dialkyl-aminopyridine again via a rearrangement pathway. Structural assignments to 2-cyanoacetyl-1-methylpyrrole 1, enaminonitrile 3, pyrrole-substituted pyran 8, and pyridine 14 were made using X-ray crystallographic analysis. Finally, 2-cyanoacetyl-1-methylpyrrole 1 undergoes coupling with benzenediazonium chloride to yield the arylhydrazone 2 that reacts with hydroxylamine hydrochloride to yield an amidoxime 19 that participates in ready cyclization to form the pyrrole-substituted 1,2,3-triazole 20 whose structure could be also established by X-ray crystallography.

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Essential Multicomponent Reactions I

Marqués‐López

Herrera

2015

Multicomponent Reactions

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Synthesis of π-conjugated thiophenes starting from substituted 3-oxopropanenitriles via Gewald reaction

Cited by 49 publications

References 46 publications

Gewald reaction: synthesis, properties and applications of substituted 2-aminothiophenes

Gewald reaction: synthesis, properties and applications of substituted 2-aminothiophenes

Studies with 3-oxoalkanenitriles: novel rearrangements observed while exploring the utility of 3-(1-methyl-2-pyrrolyl)-3-oxopropanenitrile as a precursor to pyrrole-substituted heterocyclic compounds

Essential Multicomponent Reactions I

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