Catalysis by an ionic liquid: efficient conjugate addition of thiols to electron deficient alkenes catalyzed by molten tetrabutylammonium bromide under solvent-free conditions

Ranu, Brindaban C.; Dey, Suvendu S.; Hajra, Alakananda

doi:10.1016/s0040-4020(03)00289-8

Cited by 144 publications

(39 citation statements)

References 26 publications

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“…All the methods cited above have disadvantages in terms of cost, hazardous nature, long reaction times, tedious isolation procedures and high loading of catalyst. In recent past, tetrabutyl ammonium bromide (TBABr) has emerged as mild, water-tolerant, inexpensive and environmentally compatible homogenous catalyst in various organic transformations [23,[33][34][35]. Biginelly-type compounds [36] and biscoumarine & 3,4-dihydropyrano[c]chromone derivatives [37] were also prepared by using TBABr as catalyst.…”

Section: Introductionmentioning

confidence: 99%

A facile strategy for the synthesis of highly substituted imidazole using tetrabutyl ammoniumbromide as catalyst

et al. 2011

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Section: Introductionmentioning

confidence: 99%

A facile strategy for the synthesis of highly substituted imidazole using tetrabutyl ammoniumbromide as catalyst

et al. 2011

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“…Recently, molten tetrabutylammonium bromide (TBuAmBr) has been utilized as a readily accessible IL with inherent properties like environmental compatibility, nonflammability, operational simplicity, noncorrosive nature, ease of reusability and excellent thermal and chemical stability. TBuAmBr has also been used as a tremendously useful homogeneous catalyst in diverse organic transformations [13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Poly(Amide-Imide)s Bearing a S-Valine Moiety in Molten Ionic Liquid

Mallakpour

Khania

2011

Designed Monomers and Polymers

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A study has been conducted to synthesize highly organosoluble and optically active poly(amide-imide)s via direct solution polycondensation of different aliphatic and aromatic diisocyanates with a chiral diacid monomer in the presence of molten tetrabutylammonium bromide (TBuAmBr) as a molten ionic liquid, and was compared with polymerization in traditional solvents like N-methyl-2-pyrrolidone (NMP). The step-growth polymerization of N-trimellitylimido-S-valine (1) as an optically active monomer with 4,4 -methylenebis(phenyl isocyanate) (MDI) (2a) was carried out by four different methods in the presence of pyridine (Py), dibutyltin dilaurate (DBTDL), triethylamine (TEA) as a catalyst and without catalyst, respectively. In these solutions polycondensations amino acid was used as chiral inducing agent. The optimized method of MDI (2a) was used for the polymerization of hexamethylene diisocyanate (HDI) (2b), isophorone diisocyanate (IPDI) (2c) and tolylene-2,4-diisocyanate (TDI) (2d). The resulting polymers have inherent viscosities in the range of 0.15-0.87 dl/g and were characterized with FT-IR, 1 H-NMR, elemental and thermogravimetric analysis techniques. In comparison with conventional solvents, this approach exhibited smoothly higher inherent viscosities and comparative yields and thermal stability. This process is safe and green since toxic and volatile organic solvents such as NMP were eliminated. These polymers are optically active, thermally stable and soluble in amide-type solvents.

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“…3,4 Besides, the 1,4-addition is a highly atom-efficient, green reaction, in agreement with the second principle of green chemistry, which says that the synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product. [5][6][7] In view of these aspects, there are a large number of reported methods for both basic and acidic promoted selective 1,4-additions, including heterogeneous [8][9][10][11][12][13][14][15][16] and homogeneous catalysis, [17][18][19] as well as asymmetric versions. 20,21 Thus, solid catalysts, such as basic anion-exchange resins, 8 natural 9 and synthetic phosphates, 10 montmorillonite clays, 11 solid potassium carbonate, 12 base 13 and acid supported on alumina 14 have been used to perform the 1,4-addition of thiols to a series of electron-poor alkenes.…”

Section: Introductionmentioning

confidence: 99%

“…20,21 Thus, solid catalysts, such as basic anion-exchange resins, 8 natural 9 and synthetic phosphates, 10 montmorillonite clays, 11 solid potassium carbonate, 12 base 13 and acid supported on alumina 14 have been used to perform the 1,4-addition of thiols to a series of electron-poor alkenes. Besides, the use of non-volatile and non-toxic solvents, such as water, 22,23 ionic liquids, 18,19 and ethylene glycol 24 to perform the Michael addition was also described. However, the use of solid-supported catalysts in Michael addition to α,β-unsaturated aldehydes has been scarcely explored [8][9][10][11][12][13][14][15][16] and, to the best of our knowledge, the use of glycerin as a renewable and recyclable solvent for the Michael addition of thiols to electron-poor alkenes has not been described.…”

Section: Introductionmentioning

confidence: 99%

Green Michael addition of thiols to electron deficient alkenes using KF/alumina and recyclable solvent or solvent-free conditions

Lenardão¹,

Trecha²,

Ferreira³

et al. 2009

J. Braz. Chem. Soc.

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Um método simples e eficiente foi desenvolvido para a adição conjugada de tióis ao citral na presença de KF/Al 2 O 3 em meio livre de solvente ou usando glicerina como solvente reciclável a temperatura ambiente. O método em meio livre de solvente foi aplicado com sucesso na reação direta do tiofenol com o óleo essencial de capim limão (Cymbopogon citratus), para fornecer diretamente 3,7-dimetil-3-(feniltio)oct-6-enal, um potencial agente bactericida. O método foi estendido a outros alcenos deficientes de elétrons com excelentes resultados. Para o método em meio livre de solvente, o uso de irradiação com microondas facilitou o procedimento e acelerou a reação. O sistema catalítico e a glicerina podem ser reutilizados até três vezes sem tratamento prévio, com atividade comparável.A general, clean and easy method for the conjugated addition of thiols to citral promoted by KF/ Al 2 O 3 under solvent-free or using glycerin as recyclable solvent at room temperature is described. It was found that the solvent-free protocol is applicable to the direct reaction of thiophenol with the essential oil of lemon grass (Cymbopogon citratus) to afford directly 3,7-dimethyl-3-(phenylthio) oct-6-enal, a potential bactericide agent. The method was extended to other electron-poor alkenes with excellent results. For the solvent-free protocol, the use of microwave irradiation facilitated the procedure and accelerates the reaction. The catalytic system and glycerin can be reused up to three times without previous treatment with comparable activity.

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Catalysis by an ionic liquid: efficient conjugate addition of thiols to electron deficient alkenes catalyzed by molten tetrabutylammonium bromide under solvent-free conditions

Cited by 144 publications

References 26 publications

A facile strategy for the synthesis of highly substituted imidazole using tetrabutyl ammoniumbromide as catalyst

A facile strategy for the synthesis of highly substituted imidazole using tetrabutyl ammoniumbromide as catalyst

Synthesis and Characterization of Poly(Amide-Imide)s Bearing a S-Valine Moiety in Molten Ionic Liquid

Green Michael addition of thiols to electron deficient alkenes using KF/alumina and recyclable solvent or solvent-free conditions

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