Thiophenes and their Benzo Derivatives: (iii) Synthesis and Applications

Campaigne, E.

doi:10.1016/b978-008096519-2.00065-5

Cited by 41 publications

(10 citation statements)

References 172 publications

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“…3,5); this channel is more likely to follow stepwise mechanism with more favorable thermodynamic and kinetic parameters for the cyclization of imidothioate II″G containing potassium as counterion.…”

Section: Methodsmentioning

confidence: 99%

“…The activation barriers in both stepwise and concerted cyclization mechanisms considerably decrease in going from lithium to potassium as counterion. * For communication XVII, see [1].Thiophene and its derivatives are widely used not only in organic synthesis [2] but also in practice, in particular in the manufacture of dyes, plasticizers, plastics, analytical reagents, insecticides, pharmaceuticals, and perfume compositions [3], especially in the preparation of new materials [4]. Some natural thiophene derivatives, e.g., vitamin H (biotin) play an important role in biological processes [5].…”

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confidence: 99%

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Reactions of heterocumulenes with organometallic reagents: XVIII. Quantum-chemical study on the mechanisms of formation of thiophene ring from lithium and potassium buta-2,3-dienimidothioates

Шагун

Nedolya

2011

Russ J Org Chem

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Thermodynamic stabilities of different isomers and tautomers of lithium and potassium buta-2,3-dienimidothioates (ambident N,S-centered anionic adducts derived from methoxyallenyl carbanion and methyl isothiocyanate) as real or potential precursors of 3-methoxy-N,N-dimethylthiophen-2-amine were estimated by quantum-chemical calculations in terms of the density functional theory. Gradient channels corresponding to concerted (one-step) and stepwise (two-step) mechanisms of formation of thiophene ring from the most stable conformers and tautomers were localized. The formation of thiophene structure from lithium and potassium buta-2,3-dienimidothioates in two steps via intramolecular cyclization to thiophen-2(5H)-ylidene anion and its isomerization into thienylamide was found to be more probable. The activation barriers in both stepwise and concerted cyclization mechanisms considerably decrease in going from lithium to potassium as counterion. * For communication XVII, see [1].Thiophene and its derivatives are widely used not only in organic synthesis [2] but also in practice, in particular in the manufacture of dyes, plasticizers, plastics, analytical reagents, insecticides, pharmaceuticals, and perfume compositions [3], especially in the preparation of new materials [4]. Some natural thiophene derivatives, e.g., vitamin H (biotin) play an important role in biological processes [5]. Therefore, extension of the series of these compounds and search for rational ways of their synthesis are important problems [6].We were the first to show that acetylene, allene, and butadiene carbanions and heterocumulenes, primarily isothiocyanates and isocyanates, generated in situ are universal building blocks for generally one-pot assembly of most fundamental aza, oxa, and thia heterocycles [7], including thiophehes [7-9]. While developing studies in this field, we found that the yield of thiopene considerably depends not only on the reactant structure and reaction conditions, but also on the nature of counterion. Using as an example the reaction of α-lithiated methoxyallene I with methyl isothiocyanate, leading to ambident anion II′, we obtained experimental proofs for the effect of counterion nature (Li + or K + ) on the yield of 3-methoxy-N,N-dimethylthiophen-2-amine (III) (Schemes 1, 2). In particular, we found that aminothiophene III is formed directly from intermediate II′ in 32% yield (after distillation; Scheme 1, i). It was presumed that the reaction involves intramolecular cyclization of lithium butadienimidothioate II′A (S-centered azatriene anion) with formation of iminothienyl anion IV′ with lithium as counterion and subsequent isomerization of IV′ into lithium thienylamide V′. Treatment of the latter with methyl iodide yields thiophenamine III (Scheme 2).Replacement of lithium cation in intermediate II′ by potassium (via addition of powdered potassium tert-butoxide to the reaction mixture) increases the yield of thiophenamine III to 75% (Scheme 1, ii) [9]. Likewise, the reaction is most likely to occur through

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Reactions of heterocumulenes with organometallic reagents: XVIII. Quantum-chemical study on the mechanisms of formation of thiophene ring from lithium and potassium buta-2,3-dienimidothioates

Шагун

Nedolya

2011

Russ J Org Chem

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“…• Reaction of aldehydes/ketones with primary amines under acidic/basic conditions [30] • Aldol-like condensation of aldehyde [31] • Oxidative synthesis of imines from alcohols and amines [32] • Addition of organometallic reagents to cyanides [33] • Reaction of phenols and phenol-ethers with nitriles [34] • Reaction of metal amides [35] • Synthesis of ketimines from ketals [ • Reaction of olefins and tertiary alcohols with hydrazoic acid [37] • Conversion of α-amino acids into imines [38] • Reduction of nitro compounds [39]…”

Section: Synthesis Of Schiff Bases and Derivativesmentioning

confidence: 99%

Schiff Bases and Their Metallic Derivatives: Highly Versatile Molecules with Biological and Abiological Perspective

Khan¹,

Gul²,

Khan³

2020

Stability and Applications of Coordination Compounds

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1998 onwards, a span reporting thousands of research articles describes the ever-increasing applicability of Schiff bases and their metallic complexes; this chapter comprehensively examines the literature of the last 20 years. The structural diversity of these molecules made them available for a very wide range of biological and abiological applications. Schiff bases are excellent chelators and due to this unique property have found their place in qualitative and quantitative determination of metals in aqueous media. The structural diversity of metal chelates proved these to be outstanding catalysts and displayed interesting fluorescence effect. Finally, Schiff base moieties have found a unique position during the in vitro and in vivo experiments for drug development against a huge number of biological entities including bacteria, fungi, cancer cells, viruses, parasites, etc.

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“…41,42 Briefly, exponentially, cells growing in 96-well plates were then exposed for 48 h to five serial concentrations of each compound, starting from a maximum concentration of 150 μM. Following this exposure period adherent cells were fixed, washed, and stained.…”

Section: Tumor Cell Growth Assaymentioning

confidence: 99%

Heteroannelation of Cyclic Ketones: Synthesis, Characterization and Antitumor Evaluation of Some Condensed Azine Derivatives

Soylem

Assy

Morsi

2016

ACSi

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A series of pyrimidine and thiazine derivatives was synthesized by one-pot reaction of cyclopentanone with a mixture of an aromatic aldehyde, namely o-anisaldehyde, and different ureas, namely urea, guanidine and thiourea, respectively. Furthermore, cycloaddition reaction of active methylene reagents, namely acetyl acetone, malononitrile, ethyl cyanoacetate, cyanoacetamide and N-phenyl cyanoacetamide with 2,6-bis(2-methoxybenzylidene)cyclohexanone afforded chromene and quinoline derivatives in basic medium. The antitumor evaluation of some new compounds against three human cell lines, namely MCF-7, NCI-H460 and SF-268 showed significant and moderate activity compared with the positive control doxorubicin.

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Thiophenes and their Benzo Derivatives: (iii) Synthesis and Applications

Cited by 41 publications

References 172 publications

Reactions of heterocumulenes with organometallic reagents: XVIII. Quantum-chemical study on the mechanisms of formation of thiophene ring from lithium and potassium buta-2,3-dienimidothioates

Reactions of heterocumulenes with organometallic reagents: XVIII. Quantum-chemical study on the mechanisms of formation of thiophene ring from lithium and potassium buta-2,3-dienimidothioates

Schiff Bases and Their Metallic Derivatives: Highly Versatile Molecules with Biological and Abiological Perspective

Heteroannelation of Cyclic Ketones: Synthesis, Characterization and Antitumor Evaluation of Some Condensed Azine Derivatives

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