Acceptorless dehydrogenative synthesis of benzothiazoles and benzimidazoles from alcohols or aldehydes by heterogeneous Pt catalysts under neutral conditions

Chaudhari, Chandan; Siddiki, S. M. A. Hakim; Shimizu, Ken‐ichi

doi:10.1016/j.tetlet.2015.06.073

Cited by 56 publications

(27 citation statements)

References 35 publications

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“…In mechanistic studies, we noticed that the reaction is following similar pathways as described in earlier report . Primarily ethanol was getting oxidized in presence of Rh@PS catalyst and K 2 CO 3 base, provided in situ acetaldehyde ( 4 ) as an intermediate …”

Section: Methodssupporting

confidence: 70%

Supported Rhodium (Rh@PS) Catalyzed Benzimidazoles Synthesis Using Ethanol/Methanol as C₂H₃/CH Source

Sharma

Yamini

et al. 2018

Adv Synth Catal

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An effective and stable polystyrene supported rhodium (Rh@PS) nano-catalyst has been synthesized by following reduction-deposition approach and applied for the selective benzimidazoles synthesis from 1,2-phenylenediamines and ethanol/ methanol as C 2 H 3 /CH source. The ethanol/methanol in the presence of trace amounts of aerobic oxygen under Rh@PS catalysed condition, first participated in oxidation of alcohol followed by consecutive condensation, cyclization and hydrogen elimination reactions with 1,2-phenylenediamine gave the desired products in good yields. The Rh@PS catalyst in a single system performed both oxidation and reduction reactions in a selective/ specific manner and applied for large substrate scope. Easy recovery, handling, stability, recyclability of the catalyst and less chance of metal contamination with the products are the added advantages of the process.

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Section: Methodssupporting

confidence: 70%

Supported Rhodium (Rh@PS) Catalyzed Benzimidazoles Synthesis Using Ethanol/Methanol as C₂H₃/CH Source

Sharma

Yamini

et al. 2018

Adv Synth Catal

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“…In order to find an environmentally friendly, high efficiency, low cost, high atomic and economic method for the synthesis of benzimidazoles, various heterogeneous catalytic systems such as heteropolyacid catalysts [17], modified zeolite catalysts [18], complex metal oxide catalysts [19,20], supported noble metal catalysts [21][22][23], Cu-PMO catalysts [24] and photocatalytic systems over Pt-TiO 2 [25] were recently reported. In our recent work, the direct synthesis of benzimidazoles from 2-nitroaniline and alcohol in aqueous media catalyzed by Cu-Pd/γ-Al 2 O 3 solid catalyst was studied [26].…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Catalytic Synthesis of 2-Methylbenzimidazole from 2-Nitroaniline and Ethanol Over Mg Modified Cu-Pd/γ-Al2O3

et al. 2018

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The direct synthesis of benzimidazoles from 2-nitroaniline and ethanol over Cu-Pd/γ-Al2O3 catalysts has the advantages of requiring easily available starting materials, having high efficiency, and a simple procedure. The modification by Mg of the Cu-Pd/γ-Al2O3 catalyst could improve the catalytic activity significantly. The addition of Mg to the Cu-Pd/γ-Al2O3 catalyst could maintain and promote the formation of CuPd alloy active sites. Meanwhile, the basicity of the support was enhanced appropriately by Mg, which generated more basic sites (Al-Oδ−) to accelerate the dehydrogenation of alcohol and increased the rate of the whole coupled reaction. The 2-nitroaniline was completely converted over Cu-Pd/(Mg)γ-Al2O3 after reacting for six hours, and the yield of 2-methylbenzimidazole was 98.8%. The results of this work provide a simple method to develop a more efficient catalyst for the “alcohol-dehydrogenation, hydrogen transfer and hydrogenation” coupled reaction system.

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“…The recently reported methods mostly employed homogeneous catalysts that require special work‐up and separation techniques for the recovery and recycling from the reaction environment. Some other catalysts such as mesoporous titania‐iron(III) oxide, CuO/silica, β‐cyclodextrin, Pt‐TiO 2 , α‐MoO 3 nanobelts, Fe 3 O 4 /SiO 2 /(CH 2 ) 3 N + Me 3 Br − 3 core–shell nanoparticles, and Fe 3 O 4 ‐SiO 2 ‐(NH 4 ) 6 Mo 7 O 24 magnetic core–shell nanocomposite were also used in alleviating some of the limitations. Most of these methods suffer from some drawbacks, such as the use of highly toxic or expensive reagent, long reaction times, tedious work‐up procedures, low yields of products, and, in some cases, harsh reaction conditions.…”

Section: Introductionmentioning

confidence: 99%

A novel ternary GO@SiO₂‐HPW nanocomposite as an efficient heterogeneous catalyst for the synthesis of benzazoles in aqueous media

Habibzadeh

Pasha

Tajbakhsh

et al. 2019

J Chinese Chemical Soc

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A new solid acid catalyst, consisting of 12‐phosphotungstic heteropoly acid (HPW) supported on graphene oxide/silica nanocomposite (GO@SiO2), has been developed via immobilizing HPW onto an amine‐functionalized GO/SiO2 surface through coordination interaction (GO@SiO2‐HPW). The GO@SiO2‐HPW nanocomposite was characterized by Fourier transform infrared (FT‐IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and powder X‐ray diffraction (XRD). The prepared nanocomposite could be dispersed homogeneously in water and further used as a heterogeneous, reusable, and efficient catalyst for the synthesis of benzimidazoles and benzothiazoles by the reaction of 1,2‐phenelynediamine or 2‐aminothiophenol with different aldehydes.

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Acceptorless dehydrogenative synthesis of benzothiazoles and benzimidazoles from alcohols or aldehydes by heterogeneous Pt catalysts under neutral conditions

Cited by 56 publications

References 35 publications

Supported Rhodium (Rh@PS) Catalyzed Benzimidazoles Synthesis Using Ethanol/Methanol as C₂H₃/CH Source

Supported Rhodium (Rh@PS) Catalyzed Benzimidazoles Synthesis Using Ethanol/Methanol as C₂H₃/CH Source

Heterogeneous Catalytic Synthesis of 2-Methylbenzimidazole from 2-Nitroaniline and Ethanol Over Mg Modified Cu-Pd/γ-Al2O3

A novel ternary GO@SiO₂‐HPW nanocomposite as an efficient heterogeneous catalyst for the synthesis of benzazoles in aqueous media

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Acceptorless dehydrogenative synthesis of benzothiazoles and benzimidazoles from alcohols or aldehydes by heterogeneous Pt catalysts under neutral conditions

Cited by 56 publications

References 35 publications

Supported Rhodium (Rh@PS) Catalyzed Benzimidazoles Synthesis Using Ethanol/Methanol as C2H3/CH Source

Supported Rhodium (Rh@PS) Catalyzed Benzimidazoles Synthesis Using Ethanol/Methanol as C2H3/CH Source

Heterogeneous Catalytic Synthesis of 2-Methylbenzimidazole from 2-Nitroaniline and Ethanol Over Mg Modified Cu-Pd/γ-Al2O3

A novel ternary GO@SiO2‐HPW nanocomposite as an efficient heterogeneous catalyst for the synthesis of benzazoles in aqueous media

Contact Info

Product

Resources

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Supported Rhodium (Rh@PS) Catalyzed Benzimidazoles Synthesis Using Ethanol/Methanol as C₂H₃/CH Source

Supported Rhodium (Rh@PS) Catalyzed Benzimidazoles Synthesis Using Ethanol/Methanol as C₂H₃/CH Source

A novel ternary GO@SiO₂‐HPW nanocomposite as an efficient heterogeneous catalyst for the synthesis of benzazoles in aqueous media