- A heterogeneous catalytic strategy for facile production of benzimidazoles and quinoxalines from primary amines using the Al-MCM-41 catalyst
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This study reports a straightforward heterogeneous catalytic (Al-MCM-41) approach to synthesize nitrogen heterocycle moieties from primary amines under solvent-free conditions. The Al-MCM-41 catalyst was prepared using a hydrothermal method and characterized by various analytical techniques. The probability and limitations of the catalytic methodology were presented with various substrates. The catalytic method grants an attractive route to a wide variety of benzimidazole and quinoxaline moieties with good to excellent yields. The gram scale reaction and reusability (up to five cycles) of the Al-MCM-41 catalyst would greatly benefit industrial applications. This journal is
- Vasu, Amrutham,Naresh, Mameda,Krishna Sai, Gajula,Divya Rohini, Yennamaneni,Murali, Boosa,Ramulamma, Madasu,Ramunaidu, Addipilli,Narender, Nama
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p. 9439 - 9446
(2021/12/09)
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- Nickel-catalysed dehydrogenative coupling of aromatic diamines with alcohols: Selective synthesis of substituted benzimidazoles and quinoxalines
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The first nickel-catalysed dehydrogenative coupling of primary alcohols and ethylene glycol with aromatic diamines for selective synthesis of mono- and di-substituted benzimidazoles and quinoxalines is reported. The earth-abundant, non-precious and simple NiCl2/L1 system enables the synthesis of N-heterocycles releasing water and hydrogen gas as byproducts. Mechanistic studies involving deuterium labeling experiments and quantitative determination of hydrogen gas evaluation were performed.
- Bera, Atanu,Sk, Motahar,Singh, Khushboo,Banerjee, Debasis
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supporting information
p. 5958 - 5961
(2019/05/27)
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- Synthesis and tuberculostatic activity evaluation of novel benzazoles with alkyl, cycloalkyl or pyridine moiety
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Compounds possessing benzimidazole system exhibit significant antituberculous activity. In order to examine how structure modifications affect tuberculostatic activity, a series of benzazole derivatives were synthesized and screened for their antitubercul
- Krause, Malwina,Foks, Henryk,Augustynowicz-Kope?, Ewa,Napiórkowska, Agnieszka,Szczesio, Ma?gorzata,Gobis, Katarzyna
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- Dehydrogenative synthesis of benzimidazoles under mild conditions with supported iridium catalysts
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Solid supported iridium catalysts, which show excellent activity for the dehydrogenative synthesis of benzimidazoles from primary alcohols and phenylenediamine derivatives under mild reaction conditions, were developed. Among the catalysts examined, the titania-supported iridium catalyst showed the highest activity, and benzimidazole derivatives were selectively produced at temperatures of 80°C or higher. For example, the reaction of phenylenediamine (1a) with benzyl alcohol (2a) in the presence of Ir(1.0 wt%)/TiO2 (1.0 mol%, towards 1a) at 120°C selectively gave 2-phenylbenzimidazole (3aa) in 80% yield after 6 h and over 90% yield after 18 h. A high turnover number (TON) of more than 800 was achieved in the reaction at a higher substrate-to-catalyst ratio. Reduction of the catalysts under a hydrogen atmosphere at around 500 to 600°C is essential for their significant activity. Characterization of the catalysts by gas adsorption, XRD, XPS, H2-TPR, TEM, and XAFS techniques revealed that highly-dispersed nanoparticles of the iridium(0) species (ca. 1 to 2 nm in diameter) formed on TiO2 are responsible for the catalysis. The catalysts could be recycled without a significant loss of activity, and the leaching of the iridium species into the solution during the catalytic runs was negligible, which suggests that the present catalysts would be excellent from both environmental and practical perspectives.
- Tateyama, Keisuke,Wada, Kenji,Miura, Hiroki,Hosokawa, Saburo,Abe, Ryu,Inoue, Masashi
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p. 1677 - 1684
(2016/04/05)
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- Acceptorless dehydrogenative synthesis of benzothiazoles and benzimidazoles from alcohols or aldehydes by heterogeneous Pt catalysts under neutral conditions
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Abstract Pt/Al2O3 and Pt/TiO2 were effective catalysts for the synthesis of 2-substituted benzothiazoles and benzimidazoles from 2-aminothiophenol and 1,2-phenylenediamine with alcohols or aldehydes under acceptor-free and additive-free conditions.
- Chaudhari, Chandan,Siddiki, S.M.A. Hakim,Shimizu, Ken-Ichi
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p. 4885 - 4888
(2015/07/28)
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- A novel synthetic method for the preparation of aliphatic aldehydes from the corresponding carboxylic acids
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A novel synthetic method for the preparation of aliphatic aldehydes from the corresponding carboxylic acids via 1,3-dimethylbenzimidazolium salts is provided. 1,3-Dimethylbenzimidazolium salts were rapidly reduced with sodium/ethanol and then hydrolyzed with hydrochloric acid to obtain aliphatic aldehydes, in which the 1,3-dimethylbenzimidazolium salts can be readily achieved from the corresponding carboxylic acids. The mechanism for the reductive reaction of 1,3-dimethylbenzimidazolium salts with sodium/ethanol was discussed.
- Guo, Yuan,Lu, Zhenhuan,Yao, Libo,Shi, Zhen
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scheme or table
p. 489 - 492
(2012/01/05)
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- Enzyme-mediated domino synthesis of 2-alkylbenzimidazoles in solvent-free system: A green route to heterocyclic compound
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Solvent-free domino acylation/cyclization reactions between fatty acid esters and o-phenylenediamine mediated by immobilized lipase from Mucor miehei (MML) were found to be an efficient way in the synthesis of 2- alkylbenzimidazole. Compared with other substrates, methyl fatty acid esters with moderated chain length exhibited best activity with yield up to 95%. The mechanism of the domino process was clarified deeply through some detail experiments, including separation of intermediates. This efficient enzymatic domino process provides an attractive procedure for heterocyclic compound synthesis and could be regarded as a potential synthetic method in modern organic chemistry.
- Wang, Li,Li, Chao,Wang, Na,Li, Kun,Chen, Xi,Yu, Xiao-Qi
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body text
p. 16 - 20
(2010/12/19)
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- One-pot synthesis of functionalized benzimidazoles and 1H-pyrimidines via cascade reactions of o-aminoanilines or naphthalene-1,8-diamine with alkynes and p-tolylsulfonyl azide
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A one-pot synthesis of functionalized benzimidazoles and 1H-pyrimidines via the cascade reactions of o-aminoanilines or naphthalene-1,8-diamine with terminal alkynes and p-tolylsulfonyl azide is reported. The protocol is efficient and general. Georg Thiem
- She, Jin,Jiang, Zheng,Wang, Yanguang
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experimental part
p. 2023 - 2027
(2010/03/04)
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- First simple and mild synthesis of 2-alkylbenzimidazoles involving a supported enzymatic catalyst
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A new enzymatic synthesis is described for 2-alkyl-benzimidazoles a technologically important class of compounds. It is a one-step synthesis which involves a supported enzyme (Lipozyme) and is carried out in very mild conditions in hydrocarbon solvents to give 2-alkyl-benzimidazoles in good yields, starting from the free acids. Preliminary results indicate that the reaction has a potential to produce new molecules using sensitive or conjugated acids. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Renard, Gilbert,Lerner, Dan A.
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p. 1417 - 1420
(2008/02/13)
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- Synthesis and insecticidal activity of some benzimidazolic and benzothiazolic derivatives
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The benzimidazolic and benzothiazolic derivatives with a (CH2)n radical in 2 position of the heterocycle had been synthesized and then tested for their insecticidal activity on Culex pipiens larvae. The benzothiazolic derivatives were found to be the most active. The study has also showed that this activity was related to the nature of the substitute in 2 position of the heterocycle. This activity increased when (CH2)n chain increased until n = 6; above this value, the activity decreased.
- Lahlou, M.,Weliou, M.,Salem, M.,Hajji, M. S.
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