- 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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- Direct synthesis of 2-substituted benzimidazoles: Via dehydrogenative coupling of aromatic-diamine and primary alcohol catalyzed by a Co complex
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A Co(ii) complex with a stable structure was designed and synthesized with quinalic acid and Co (OAc)2·4H2O. The single crystal structure of the complex was characterized by X-ray diffraction. A dehydrogenative coupling of aromatic diamines and primary alcohols was developed by using the Co(ii) complex as the catalyst to synthesize 2-substituted benzimidazole. A series of 2-substituted benzimidazoles were obtained with good to excellent yields under mild reaction conditions. In addition, a compound with inhibitory Parkinson's activity was synthesized on a gram-scale by using this method. Finally, the reaction mechanism was proposed and the energy changes in the reaction process were simulated by density functional theory (DFT).
- Zuo, Minghui,Guo, Weihao,Pang, Yucheng,Guo, Rui,Hou, Chuanfu,Sun, Shouneng,Wu, Hongfeng,Sun, Zhizhong,Chu, Wenyi
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p. 14490 - 14495
(2020/10/03)
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- Method for preparing benzimidazole and quinazoline compounds by adopting supported nickel catalyst (by machine translation)
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The invention discloses a method for synthesizing benzimidazole and quinazoline compounds by oxidative coupling and dehydrogenation of a nitrogen-doped hierarchical porous biomass-based carbon material supported catalyst and a preparation method. The method comprises the following steps: adding o-phenylenediamine compound, alcohol, supported catalyst, toluene and potassium tert-butoxide as a solvent, carrying out reaction under 50~150 °C conditions, carrying out reaction 4~24 hours, cooling to room temperature, filtering the reaction liquid, and obtaining a benzimidazole compound or quinazoline compound. The method adopts "one-pot method" preparation, the intermediate can be separated and purified, energy consumption can be reduced, and the efficiency. (by machine translation)
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Paragraph 0054-0056; 0057; 0059
(2019/07/16)
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- Selective Synthesis of 2-Substituted and 1,2-Disubstituted Benzimidazoles Directly from Aromatic Diamines and Alcohols Catalyzed by Molecularly Defined Nonphosphine Manganese(I) Complex
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Herein, we present a selective synthesis of 2-substituted and 1,2-disubstituted benzimidazoles by acceptorless dehydrogenative coupling of aromatic diamine with primary alcohols. The reaction is catalyzed by a phosphine-free tridentate NNS ligand-derived manganese(I) complex.
- Das, Kalicharan,Mondal, Avijit,Srimani, Dipankar
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p. 9553 - 9560
(2018/07/21)
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- Sulfonic-acid-functionalized activated carbon made from tea leaves as green catalyst for synthesis of 2-substituted benzimidazole and benzothiazole
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Abstract: A simple and efficient procedure for synthesis of 2-substituted benzimidazole and benzothiazole has been developed by using sulfonic-acid-functionalized activated carbon as heterogeneous catalyst. The activated material was prepared from matured tea leaf in presence of phosphoric acid as activating agent. The final catalyst was prepared by anchoring –SO3H group on the surface of the activated carbon. The catalyst could be easily recovered and reused for more than three catalytic cycles without significant loss in catalytic activity. The catalytic performance of the catalyst was found to be superior to that of a similar catalyst prepared from montmorillonite K10. Graphical Abstract: [Figure not available: see fulltext.].
- Goswami, Mridusmita,Dutta, Mintu Maan,Phukan, Prodeep
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p. 1597 - 1615
(2017/11/17)
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- Synthesis, anti-proliferative activity, SAR study, and preliminary in vivo toxicity study of substituted N,N′-bis(arylmethyl)benzimidazolium salts against a panel of non-small cell lung cancer cell lines
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A series of N,N′-bis(arylmethyl)benzimidazolium salts have been synthesized and evaluated for their in vitro anti-cancer activity against select non-small cell lung cancer cell lines to create a structure activity relationship profile. The results indicate that hydrophobic substituents on the salts increase the overall anti-proliferative activity. Our data confirms that naphthylmethyl substituents at the nitrogen atoms (N1(N3)) and highly lipophilic substituents at the carbon atoms (C2and C5(C6)) can generate benzimidazolium salts with anti-proliferative activity that is comparable to that of cisplatin. The National Cancer Institute's Developmental Therapeutics Program tested 1, 3–5, 10, 11, 13–18, 20–25, and 28–30 in their 60 human tumor cell line screen. Results were supportive of data observed in our lab. Compounds with hydrophobic substituents have higher anti-cancer activity than compounds with hydrophilic substituents.
- Shelton, Kerri L.,DeBord, Michael A.,Wagers, Patrick O.,Southerland, Marie R.,Williams, Travis M.,Robishaw, Nikki K.,Shriver, Leah P.,Tessier, Claire A.,Panzner, Matthew J.,Youngs, Wiley J.
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p. 421 - 439
(2016/12/18)
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- New telmisartan-derived PPARγ agonists: Impact of the 3D-binding mode on the pharmacological profile
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In previous studies, the 4′-((2-propyl-1H-benzo[d]imidazol-1-yl)methyl)-[1,1′-biphenyl]-2-carboxylic acid was identified as pharmacophoric core for PPARγ activation. In this structure-activity relationship study the C2-alkyl chain was elongated and the 2-COOH group was changed to a carbamide/carbonitrile or shifted to the 3- or 4-position. Furthermore, the benzo[d]imidazole was exchanged by 2,3-dihydrobenzo[d]thiazole or 1H-indole. C2-propyl derivatives showed the profile of partial agonists, while elongation of the C2-chain to that of an n-heptyl group or a 4-COOH shift changed the pharmacological profile to that of a potent full agonist. This finding can be explained by binding to the LBD in different ligand conformations. Two anchoring points (Tyr473 and Arg288) exist in the LBD, which have to be contacted to achieve receptor activation. In a crystal violet chemosensitivity assay using COS-7?cells and LNCaP cells expressing PPARγ only the carbamide derivatives influenced the cell growth, independently on the presence of the PPARγ. Therefore, receptor mediated cytotoxicity can be excluded.
- Obermoser, Victoria,Urban, Margarethe E.,Murgueitio, Manuela S.,Wolber, Gerhard,Kintscher, Ulrich,Gust, Ronald
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p. 138 - 152
(2016/08/30)
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- Synthesis of Benzimidazoles via Iron-Catalyzed Aerobic Oxidation Reaction of Imine Derivatives with o-Phenylenediamine
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A simple and efficient protocol for preparing benzimidazoles via Fe(NO3)3.9H2O-catalyzed aerobic oxidation reaction of imine derivatives with o-phenylenediamine. This process uses air as an economical and green oxidant, tolerates a wide range of substrates, and affords the targeted benzimidazoles in moderate to excellent yields.
- Yu, Jiatao,Lu, Ming
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supporting information
p. 2148 - 2157
(2015/09/01)
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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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- Iron(II) bromide-catalyzed oxidative coupling of benzylamines with ortho-substituted anilines: Synthesis of 1,3-benzazoles
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An iron(II) bromide-catalyzed oxidative coupling of benzylamines with 2-amino/hydroxy/mercapto-anilines has been developed, allowing the synthesis of a diversity of substituted 1,3-benzazoles in good to excellent yields. This transformation is compatible with a wide range of functional groups. The method is practical, economical and employs molecular oxygen as an oxidant.
- Gopalaiah, Kovuru,Chandrudu, Sankala Naga
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p. 5015 - 5023
(2015/03/03)
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- The synthesis of benzimidazoles and quinoxalines from aromatic diamines and alcohols by iridium-catalyzed acceptorless dehydrogenative alkylation
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Benzimidazoles and quinoxalines are important N-heteroaromatics with many applications in pharmaceutical and chemical industry. Here, the synthesis of both classes of compounds starting from aromatic diamines and alcohols (benzimidazoles) or diols (quinoxalines) is reported. The reactions proceed through acceptorless dehydrogenative condensation steps. Water and two equivalents of hydrogen are liberated in the course of the reactions. An Ir complex stabilized by the tridentate P^N^P ligand N2,N 6-bis(di-isopropylphosphino)pyridine-2,6-diamine revealed the highest catalytic activity for both reactions. Aromatic diamines were reacted with alcohols and diols to form benzimidazoles or quinoxalines, respectively (see scheme). In the course of the reactions, water and two equivalents of hydrogen gas were eliminated/liberated. An Ir complex stabilized by a tridentate PNP ligand was found to be an efficient catalyst in these reactions.
- Hille, Toni,Irrgang, Torsten,Kempe, Rhett
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supporting information
p. 5569 - 5572
(2014/05/20)
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- Visible-light-promoted synthesis of benzimidazoles
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A simple and environmentally-friendly synthetic method for benzimidazoles, which are important structural motifs in many applications owing to their various biological functions, has been developed. The reaction of o-phenylenediamine and a variety of aliphatic/aromatic aldehydes in methanol proceeds at room temperature with only natural sources, molecular oxygen and visible light. A simple and eco-friendly synthetic method for benzimidazoles, which are important structural motifs in many applications owing to their various biological functions, has been developed. The reaction of o-phenylenediamine and a variety of aliphatic/aromatic aldehydes in methanol proceeds at room temperature with only natural sources, molecular oxygen and visible light. Copyright
- Park, Sehyun,Jung, Jaehun,Cho, Eun Jin
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p. 4148 - 4154
(2014/07/08)
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- Metal-free aerobic oxidative C-N bond cleavage of tertiary amines for the synthesis of N-heterocycles with high atom efficiency
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An efficient metal-free aerobic oxidative C-N bond cleavage of tertiary amines has been developed to construct N-heterocycles using molecular oxygen as the sole oxidant with high atom efficiency, in which all of the three alkyl groups in tertiary amines can be utilized and transformed into N-heterocycles. This journal is the Partner Organisations 2014.
- Chen, Xiuling,Chen, Tieqiao,Zhou, Yongbo,Han, Daoqing,Han, Li-Biao,Yin, Shuang-Feng
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supporting information
p. 3802 - 3807
(2014/06/09)
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- Cobalt- and iron-catalyzed redox condensation of o-substituted nitrobenzenes with alkylamines: A step- and redox-economical synthesis of diazaheterocycles
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A wide variety of functionalized 2-aryl benzimidazoles can be prepared by a solvent-free cobalt- or iron-catalyzed redox condensation of 2-nitroanilines and benzylamines. The cascade including benzylamine oxidation, nitro reduction, condensation, and aromatization occurs without any added reducing or oxidizing agent. The method can be extended to other alkylamines as reducing components or 2-nitrobenzamides as oxidizing components when using an iron/sulfur catalyst to afford various diazaheterocycles.
- Nguyen, Thanh Binh,Bescont, Julie Le,Ermolenko, Ludmila,Al-Mourabit, Ali
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supporting information
p. 6218 - 6221
(2014/01/17)
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- A general approach to substituted benzimidazoles and benzoxazoles via heterogeneous palladium-catalyzed hydrogen-transfer with primary amines
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The synthesis of benzimidazoles starting from o-phenylenediamines and amines in the presence of palladium on charcoal as catalyst is reported. Under microwave dielectric heating it is possible to use a tertiary, a secondary, and even a primary amine as the substrate for a palladium-mediated process to get 2-substituted or 1,2-disubstituted benzimidazoles, depending on the nature of the o-phenylenediamine employed. Primary amines are the most suitable reagents for the atom economy of the overall process that resulted to be general as several different substituted benzimidazoles were obtained in good yield. Benzoxazoles can be also prepared starting from primary amines and o-aminophenol. The reaction is also highly selective as no (poly)-alkylated phenylenediamines or cross-contaminated benzimidazoles are obtained starting from N-monoalkylphenylenediamines. This behavior was interpreted as a scarce aptitude to dehydrogenation of the methylene bonded to the aromatic NH of N-alkylarylamines. The experiments carried out consent to draw an almost complete picture of the reaction pathways occurring during the process. The catalyst can be recycled several times and, although far from optimal performances, catalyst TON=90 is encouraging for further large-scale optimization protocols. In addition, the palladium on charcoal-catalyzed microwave-assisted reaction of o-phenylenediamine gives de-alkylation of tertiary amines and transformation into the secondary ones. Copyright
- Pizzetti, Marianna,De Luca, Elisa,Petricci, Elena,Taddei, Maurizio,Porcheddu, Andrea
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p. 2453 - 2464,12
(2012/12/12)
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- A general approach to substituted benzimidazoles and benzoxazoles via heterogeneous palladium-catalyzed hydrogen-transfer with primary amines
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The synthesis of benzimidazoles starting from o-phenylenediamines and amines in the presence of palladium on charcoal as catalyst is reported. Under microwave dielectric heating it is possible to use a tertiary, a secondary, and even a primary amine as the substrate for a palladium-mediated process to get 2-substituted or 1,2-disubstituted benzimidazoles, depending on the nature of the o-phenylenediamine employed. Primary amines are the most suitable reagents for the atom economy of the overall process that resulted to be general as several different substituted benzimidazoles were obtained in good yield. Benzoxazoles can be also prepared starting from primary amines and o-aminophenol. The reaction is also highly selective as no (poly)-alkylated phenylenediamines or cross-contaminated benzimidazoles are obtained starting from N-monoalkylphenylenediamines. This behavior was interpreted as a scarce aptitude to dehydrogenation of the methylene bonded to the aromatic NH of N-alkylarylamines. The experiments carried out consent to draw an almost complete picture of the reaction pathways occurring during the process. The catalyst can be recycled several times and, although far from optimal performances, catalyst TON=90 is encouraging for further large-scale optimization protocols. In addition, the palladium on charcoal-catalyzed microwave-assisted reaction of o-phenylenediamine gives de-alkylation of tertiary amines and transformation into the secondary ones. Copyright
- Pizzetti, Marianna,De Luca, Elisa,Petricci, Elena,Porcheddu, Andrea,Taddei, Maurizio
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p. 2453 - 2464
(2013/01/14)
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- Mild and highly efficient protocol for the synthesis of benzimidazoles using samarium triflate [Sm(OTf)3]
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One-pot synthesis of benzimidazole compounds from ortho-phenylenediamine and a variety of aldehydes was developed under mild reaction conditions. All the reactions were carried out in the presence of samarium triflate (10mol%) in acetonitrile at room temperature. Copyright Taylor & Francis Group, LLC.
- Narsaiah, A. Venkat,Reddy, A. Ramesh,Yadav
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experimental part
p. 262 - 267
(2011/03/20)
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- Room temperature synthesis of benzimidazole derivatives using reusable cobalt hydroxide (II) and cobalt oxide (II) as efficient solid catalysts
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Here we demonstrate the synthesis of benzimidazoles through the coupling of 1,2-phenylenediamine with aldehydes by using Co(OH)2 and similarly CoO(II) as efficient solid catalysts in ethanol at room temperature. The Co(OH)2 solid catalyst gave better yields (82-98%) in short reaction times (4-7 h) than CoO(II) catalyst (80-94%, 6-9 h). These commercially available cheap catalysts are more active than many reported expensive heterogeneous catalysts.
- Adharvana Chari, Murugulla,Shobha, Donthabhakthuni,Sasaki, Takehiko
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experimental part
p. 5575 - 5580
(2011/11/06)
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- An inorganic iodine-catalyzed oxidative system for the synthesis of benzimidazoles using hydrogen peroxide under ambient conditions
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A simple and efficient catalytic oxidative system for the synthesis of benzimidazole derivatives with H2O2 in the presence of catalytic amounts of Bu4NI is developed. The formation of highly reactive iodine (III) intermediate [Bu4N]+[IO 2]- is detected by ESI-MS for the first time, and a possible mechanism for the oxidation is proposed.
- Zhu, Chenjie,Wei, Yunyang
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experimental part
p. 1082 - 1086
(2012/04/17)
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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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- 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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