- Oxone-mediated annulation of 2-aminobenzamides and 1,2-diaminobenzenes with: Sec -amines via imine- N -oxides: New syntheses of 2,3-dihydroquinazolin-4(1 H)-ones and 1 H -benzimidazoles
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An efficient and mild method for the preparation of 2,3-dihydroquinazolin-4(1H)-ones and 1H-benzimidazoles by the oxone-mediated reaction of sec-amines via imine-N-oxides with 2-amino-N-substituted benzamides and 1,2-diaminobenzenes respectively in THF-wa
- Sriramoju, Vinodkumar,Kurva, Srinivas,Madabhushi, Sridhar
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Read Online
- New Synthetic Applications of Aryllead Triacetates. N-Arylation of Azoles
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Treatment of a variety of azoles or their anions with p-tolyllead triacetate in the presence of copper(II) acetate afforded the corresponding N-aryl derivatives, normally in excellent yields.Room temperature arylation of an aminobenzimidazole derivative was chemoselectively directed to the amino group.
- Lopez-Alvarado, Pilar,Avendano, Carmen,Menendez, J. Carlos
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Read Online
- Functional POM-catalyst for selective oxidative dehydrogenative couplings under aerobic conditions
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Development of selective and efficient reusable catalytic systems for sustainable chemical production under benign conditions is attractive and received much attention. Herein, we report a rod-shaped octadecyl trimethylammonium functionalized Keggin-type polyoxometalate [PMO12O40] hybrids (OTA-POM) as an efficient heterogeneous catalyst for selective oxidative dehydrogenative couplings under aerobic conditions without any additive or external base. The catalyst recovery and subsequent five successive recyclability studies of hybrid POM confirms the heterogeneous nature of present catalytic system.
- Samaraj, Elavarasan,Balaraman, Ekambaram,Manickam, Sasidharan
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- Cinnamide derived pyrimidine-benzimidazole hybrids as tubulin inhibitors: Synthesis, in silico and cell growth inhibition studies
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An approach in modern medicinal chemistry to discover novel bioactive compounds is by mimicking diverse complementary pharmacophores. In extension of this strategy, a new class of piperazine-linked cinnamide derivatives of benzimidazole-pyrimidine hybrids have been designed and synthesized. Their in vitro cytotoxicity profiles were explored on selected human cancer cell lines. Specifically, structural comparison of target hybrids with tubulin-DAMA-colchicine and tubulin-nocodazole complexes has exposed a deep position of benzimidazole ring into the αT5 loop. All the synthesized compounds were demonstrated modest to interesting cytotoxicity against different cancer cell lines. The utmost cytotoxicity has shown with an amine linker of benzimidazole-pyrimidine series, with specificity toward A549 (lung cancer) cell line. The most potent compound in this series was 18i, which inhibited cancer cell growth at micromolar concentrations ranging 2.21–7.29 μM. Flow cytometry studies disclosed that 18i inhibited the cells in G2/M phase of cell cycle. The potent antitumor activity of 18i resulted from enhanced microtubule disruption at a similar level as nocodazole on β-tubulin antibody, explored using immunofluorescence staining. The most active compound 18i also inhibited tubulin polymerization with an IC50 of 5.72 ± 0.51 μM. In vitro biological analysis of 18i presented apoptosis induction on A549 cells with triggering of ROS generation and loss of mitochondrial membrane potential, resulting in DNA injury. In addition, 18i displayed impairment in cellular migration and inhibited the colony formation. Notably, the safety profile of most potent compound 18i was revealed by screening against normal human pulmonary epithelial cells (L132: IC50: 69.25 ± 5.95 μM). The detailed binding interactions of 18i with tubulin was investigated by employing molecular docking, superimposition and free energy analyses. Thus remarks made in this study established that pyrimidine-benzimidazole hybrids as a new class of tubulin polymerization inhibitors with significant anticancer activity.
- Sana, Sravani,Reddy, Velma Ganga,Srinivasa Reddy,Tokala, Ramya,Kumar, Rahul,Bhargava, Suresh K.,Shankaraiah, Nagula
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- Visible light promoted tandem dehydrogenation-deaminative cyclocondensation under aerobic conditions for the synthesis of 2-aryl benzimidazoles/quinoxalines fromortho-phenylenediamines and arylmethyl/ethyl amines
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Visible light promoted domino synthesis of 2-aryl benzimidazoles is reported through the reaction ofortho-phenylenediamines and arylmethyl amines under aerobic conditions. The methodology has wide substrate scope and tolerates a wide range of functional groups affording the products in high yields. The use of arylethyl amines instead of arylmethyl amines gives 2-aryl quinoxalines.
- Sofi, Firdoos Ahmad,Sharma, Rohit,Rawat, Ravi,Chakraborti, Asit K.,Bharatam, Prasad V.
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supporting information
p. 4569 - 4573
(2021/03/22)
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- A one-pot synthesis of benzimidazoles via aerobic oxidative condensation of benzyl alcohols with o-phenylenediamines catalyzed by [MIMPs]+Cl-/NaNO2/TEMPO
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The ionic liquid 1-methyl-3-(3-sulfopropyl)imidazolium chloride ([MIMPs]+Cl-) in combination with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and sodium nitrite (NaNO2) as a catalytic system demonstrates high efficiency in the one-pot two-step aerobic oxidative condensation of benzyl alcohols with 1,2-phenylenediamines to give benzimidazoles. Various benzimidazoles are obtained in good to excellent yields by this strategy.
- Geng, Zhenzhen,Zhang, Hong-Yu,Yin, Guohui,Zhang, Yuecheng,Zhao, Jiquan
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p. 557 - 565
(2020/03/30)
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- Hypervalent iodine promoted: Ortho diversification: 2-aryl benzimidazole, quinazoline and imidazopyridine as directing templates
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The mild and efficient palladium-catalyzed ortho C(sp2)-H diversification of (NH)-free 2-substituted benzimidazole, quinazoline, and imidazopyridine is reported using hypervalent iodine as the key reagent. Acetoxy, aryl, iodide and nitro functi
- Saha, Moumita,Das, Asish R.
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supporting information
p. 941 - 955
(2020/02/15)
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- Method used for rapid preparation of benzo-heterocycle compound with physical grinding under solvent-free room temperature conditions
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The invention discloses a method used for rapid preparation of benzo-heterocycle compound with physical grinding under solvent-free room temperature conditions. According to the method, glacial aceticacid is taken as a catalyst; at solvent-free room temperature conditions, physical grinding is adopted, reaction of 2-substituted arylamines (2-mercapto arylamine, 2-aminophenol, and o-phenylenediamine) and aromatic aldehydes is carried out using physical grinding. The method is friendly to the environment, is simple in operation, is safe, is low in cost, and is high in efficiency. Compared withthe prior art, the advantages are that: the method is suitable for a large amount of functional groups, yield is high, less by-product is generated, operation is simple, the method is safe, cost is low, and the method is friendly to the environment.
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Paragraph 0018; 0056
(2019/01/21)
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- A novel ternary GO@SiO2-HPW nanocomposite as an efficient heterogeneous catalyst for the synthesis of benzazoles in aqueous media
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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.
- Habibzadeh, Setareh,Firouzzadeh Pasha, Ghasem,Tajbakhsh, Mahmood,Amiri Andi, Nasim,Alaee, Ehsan
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p. 934 - 944
(2019/06/13)
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- Transcriptome analysis predicts mode of action of benzimidazole molecules against Staphylococcus aureus UAMS-1
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Antimicrobial drug resistance is one of the most critical problems that plagued the human race in modern times. Discovery of novel antibiotics is important to counter this threat. Accordingly, herein we have reported the discovery of substituted benzimidazole class of molecules with antimicrobial property (specifically against Staphylococcus aureus). They were initially identified through a random screening and a novel catalytic synthetic strategy was utilized to access them. in vitro screening and phenotypic profiling revealed the antimicrobial nature. De novo transcriptome and gene analyses predicted the putative targets. This work provides a solid foundation for developing the benzimidazoles as a target specific antimicrobial preclinical candidate.
- Chauhan, Deepika,Hati, Santanu,Priyadarshini, Richa,Sen, Subhabrata
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p. 490 - 503
(2019/06/20)
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- Additive- and Oxidant-Free Expedient Synthesis of Benzimidazoles Catalyzed by Cobalt Nanocomposites on N-Doped Carbon
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A one-pot direct synthesis of a wide range of biologically active benzimidazoles through coupling of phenylenediamines and aldehydes catalyzed by a highly recyclable nonnoble cobalt nanocomposite was developed. A broad set of benzimidazoles can be efficiently synthesized in high yields and with good functional-group tolerance under additive- and oxidant-free mild conditions. The catalyst can be easily recycled for successive uses, and the process permits gram-scale syntheses of benzimidazoles.
- Wang, Zhaozhan,Song, Tao,Yang, Yong
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supporting information
p. 319 - 324
(2019/02/12)
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- An efficient NaHSO3-promoted protocol for chemoselective synthesis of 2-substituted benzimidazoles in water
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An efficient protocol for chemoselective synthesis of 2-substituted benzimidazoles from a variety of aliphatic/aromatic/ heteroaryl aldehydes and o-phenylenediamine derivatives promoted by NaHSO3 in water had been developed. The amount of NaHSO3 had a great effect on the reaction selectivity of 2-substituted benzimidazole and 1,2-disubstituted benzimidazole when the reaction was carried out in water. When the amount of the NaHSO3 was more than 11 equivalents, the 2-substituted benzimidazole could be highly selectively formed as the sole product. NaHSO3 was firstly reacted with aldehyde to form the aldehyde sodium bisulfite, which reacted with o-phenylenediamine to form the 2-substituted benzimidazole and inhibited the formation of 1,2-disubstituted benzimidazole. This protocol solved the poor selectivity problem appearing in traditional method when cyclocondensation between o-phenylenediamine and aldehydes. The method also had advantage of simple work up by filtrating the single 2-substituted benzimidazole precipitates from reaction mixture at the end of the reaction without further purification. In addition, the method was applicable to both electron-rich and electron-poor starting materials, which was successfully used for synthesizing nine novel 2-substituted benzimidazole derivatives containing a 1,2,3-triazole moiety. They were characterized by NMR, IR and HRMS spectrum. Moreover, this method had been applied to a large scale synthesis of 2-substituted benzimidazole derivatives.
- Jiang, Yu-Qin,Jia, Shu-Hong,Li, Xi-Yong,Sun, Ya-Min,Li, Wei,Zhang, Wei-Wei,Xu, Gui-Qing
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p. 1265 - 1276
(2019/01/28)
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- Biomass-Derived N-doped Carbon Materials with Silica-Supported Ultrasmall ZnO Nanoparticles: Robust Catalysts for the Green Synthesis of Benzimidazoles
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Ultrasmall ZnO nanoparticles anchored on N-doped carbon materials with a silica support (ZnO/SiO2-NC) were fabricated from chitosan and metal ions by using a one-pot self-assembly strategy and were successfully applied to the synthesis of 2-arylbenzimidazoles under mild conditions. These catalysts showed excellent stability and could be used six times without any loss of conversion and selectivity. The use of silica gel and the biomass chitosan as a source of hydrophilic N-doped carbon materials facilitated the uniform dispersion of the ZnO nanoparticles in methanol and therefore the contact of these nanoparticles with reactants, thus contributing to a high catalytic performance. TEM analysis showed that the ZnO nanoparticles were around 2.55 nm in diameter and uniformly distributed on the support surface. The binding behavior of ZnO and N-doped carbon materials affected the catalytic activity. Interestingly, temperature-programmed NH3 desorption indicated that the interactions between ZnO and N-doped carbon materials might induce the presence of more acidic sites in these catalysts, thus resulting in enhanced activity and hence promoting this transformation.
- Chen, Bo,Zhang, Chan,Niu, Libo,Shi, Xiaozhen,Zhang, Huiling,Lan, Xingwang,Bai, Guoyi
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p. 3481 - 3487
(2018/03/21)
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- A Tandem Aerobic Photocatalytic Synthesis of Benzimidazoles by Cobalt Ascorbic Acid Complex Coated on TiO2 Nanoparticles Under Visible Light
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Abstract: In this study, we developed methods for the one pot environmentally benign synthesis of benzimidazoles by cobalt ascorbic acid complex coated on TiO2 nanoparticles via aerobic photooxidative cyclization reactions. Easy work-up procedure, reusability of the catalyst and scalable to the multi-mole scale, which is valuable for an industrial process make these catalytic systems highly attractive. Also, the combination of photocatalytic and catalytic reactions presented here may help to develop a new strategy towards the development of photocatalysis-based organic synthesis. Graphical Abstract: [Figure not available: see fulltext.].
- Feizpour, Fahimeh,Jafarpour, Maasoumeh,Rezaeifard, Abdolreza
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- Metal-free synthesis of N-containing heterocycles from O-substituted aniline derivatives via 2,4,6-trihydroxybenzoic acid-catalyzed oxidative dehydrogenation of benzylamines under oxygen atmosphere
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A series of N-heterocycles, i.e., benzimidazoles, benzoxazoles, and benzothiazoles, can be conveniently synthesized by the oxidative cyclization of benzylamines with o-substituted aniline derivatives, i.e., o-phenylenediamines, o-aminophenols, and o-aminothiophenols, using 2,4,6-trihydroxybenzoic acid as an organocatalyst under an oxygen atmosphere. This approach provides a mild and efficient tool towards benzimidazoles and benzothiazoles with good yields and a broad substrate scope. The developed synthesis of N-heterocycles might proceed via the oxidative dehydrogenation of benzylamines (ArCH2NH2), generating the corresponding imines (ArCH=NH) as key intermediates.
- Kumazawa, Shun,Uematsu, Akinori,Dong, Chun-Ping,Kodama, Shintaro,Nomoto, Akihiro,Ueshima, Michio,Ogawa, Akiya
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p. 842 - 853
(2019/04/26)
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- Method for catalytically synthesizing benzimidazole compound by organic protonic acid under condition of no solvent
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The invention discloses a method for catalytically synthesizing a benzimidazole compound by organic protonic acid under the condition of no solvent. According to the method provided by the invention,high efficiency catalysis is carried out to rapidly prep
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Paragraph 0015; 0058
(2018/11/27)
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- Synthesis of benzimidazoles by Cul-catalyzed three-component reaction of 2-haloaniline, ammonia and aldehyde in water
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An efficient copper-catalyzed three-component reaction of 2-haloaniline, ammonia and aldehyde for the synthesis of benzimidazoles with 1,10-phenanthroline as the ligand has been developed. A variety of substituted benzimidazole derivatives can be obtained in yields up to 95%.
- Ke, Fang,Zhang, Peng,Lin, Chen,Lin, Xiaoyan,Xu, Jianhua,Zhou, Xiangge
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supporting information
p. 8090 - 8094
(2018/11/23)
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- Microwave-Assisted Nickel-Catalyzed Synthesis of Benzimidazoles: Ammonia as a Cheap and Nontoxic Nitrogen Source
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An efficient and convenient Ni-catalyzed C-N bond formation for the synthesis of various benzimidazoles from various 2-haloanilines, aldehydes, and ammonia in a concise manner is reported. This protocol uses commercially available, nonhazardous, clean ammonia as a reaction partner instead of other nitrogen sources. Benzimidazoles, as the sole products, were obtained in high to excellent yields (up to 95%).
- Ke, Fang,Zhang, Peng,Xu, Yiwen,Lin, Xiaoyan,Lin, Jin,Lin, Chen,Xu, Jianhua
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supporting information
p. 2722 - 2726
(2018/12/14)
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- Mild, one-pot preparation of 2-substituted benzimidazoles from organic halides
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Alkyl halides are feasibly transformed into benzimidazoles by a domino reaction under solvent-free conditions. The organic halides react with o-phenylenediamines in stoichiometric amounts in the presence of pyridine-N-oxide to produce the desired substituted benzimidazoles. This domino synthesis does not require catalysts. The synthesis occurs in dry medium and the environmental impact is minimal. The method provides products without intermediate separation. A mechanism of benzimidazole synthesis is also proposed.
- Br?tulescu, George
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supporting information
p. 811 - 817
(2017/04/06)
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- COMPOUNDS FOR TREATMENT OF TRYPANOSOMES AND NEUROLOGICAL PATHOGENS AND USES THEREOF
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The present invention relates to novel compounds that cross the blood-brain barrier and are effective inhibitors of neurological pathogens such as trypanosomes. The invention further relates to the use of these compounds for treating disorders related to trypanosomes and neurological pathogens.
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- A practical green synthesis and biological evaluation of benzimidazoles against two neglected tropical diseases: Chagas and leishmaniasis
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Antimicrobial resistance is an ever-increasing problem throughout the world and has already reached severe proportions. Two very common neglected tropical diseases are Chagas' disease and leishmaniasis. Chagas' disease is a severe health problem, mainly in Latin America, causing approximately 50000 deaths a year and millions of people are infected. About 25-30% of the patients infected with Trypanosoma cruzi develop the chronic form of the disease. On the other hand, Leishmaniasis represents complex diseases with an important clinical and epidemiological diversity. It is endemic in 88 countries 72 of which are developing countries and it has been estimated that are 12 million people infected and 350 million are in areas with infection risk. On this basis, research on organic compounds that can be used against these two diseases is an important target. A very simple, green, and efficient protocol is developed in which bismuth nitrate pentahydrate is employed as a Lewis acid catalyst in aqueous media under microwave irradiation for the synthesis of various 2-aryl substituted benzimidazoles from aldehydes and o-phenylenediamine. Other salient features of this protocol include milder conditions, atom-economy, easy extraction, and no wastes. Nine 1H-benzimidazole derivatives (1-9) with substituents at positions 2 and 5 were synthesized and the structure of the compounds was elucidated by spectroscopic methods. The compounds were screened to identify whether they posses pharmacological activity against Chagas' disease and leishmaniasis. Compound 8 showed better activity than the control Nifurtimox against INC-5 Trypanosoma cruzi strain whereas compounds 3 and 9 have demonstrated potent leshmanicidal activity. A systematic green synthetic procedure and in vitro biological evaluation of nine 1H-benzimidazoles are described.
- Bandyopadhyay, Debashis,Samano, Selina,Villalobos-Rocha, Juan Carlos,Sanchez-Torres, Luvia Enid,Nogueda-Torres, Benjamin,Rivera, Gildardo,Banik, Bimal K.
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p. 4714 - 4725
(2018/02/14)
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- Eco-friendly highly efficient solvent free synthesis of benzimidazole derivatives over sulfonic acid functionalized graphene oxide in ambient condition
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Abstract: Sulfonated graphene oxide (GO-HSO3) heterogeneous catalyst was prepared at molecular level and characterized by using various modern analytic and spectroscopic methods. Using prepared heterogeneous catalyst GO-HSO3, benzimidazole synthesis was carried out by means of reacting diamine and aldehyde at room temperature in solvent free condition. The catalyst GO-HSO3 showed tremendous catalytic activity in selective synthesis of benzimidazole, as a result 100?% conversion of reactants and up to 89.0?% yield of respective benzimidazole was achieved using 0.1?mg of catalyst in very short reaction duration. The GO-HSO3 catalyst was separated from the reaction mixture by simple filtration process at the end of reaction and reused for six successive cycles without noteworthy loss of catalytic activity and selectivity. Key advantageous of this protocol is high yield, low cost, and easy work-up procedure as well as short reaction time and solvent free condition. The present method is found eco-friendly, highly efficient, solvent free, high yielding, and clean method for the synthesis benzimidazole derivatives at room temperature. Graphical Abstract: [Figure not available: see fulltext.]
- Swami, Mantosh B.,Jadhav, Arvind H.,Mathpati, Sushil R.,Ghuge, Hanmant G.,Patil, Sudhakar G.
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p. 2033 - 2053
(2017/03/22)
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- METHOD FOR THE SYNTHESIS OF BENZAZOLE
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PROBLEM TO BE SOLVED: To obtain a benzazole in a short reaction time with high yields. SOLUTION: A method for the synthesis of a benzazole includes a chemical reaction represented by the chemical reaction formula (1) to occur in subcritical water or supercritical water (X is NR6, O, or S. Y is H, OR7, halogen, or NR8R9. R1 to R9 are a C1-C20 aliphatic or aromatic substituent which may have O, N, S, B, Si, halogen, or P (two or more substituents of R1 to R6 may be coupled together, R8 and R9 may be coupled together, and two or more substituents of R1 to R9 may be the same) or H). SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0045
(2017/09/19)
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- Oxidative Synthesis of Benzimidazoles, Quinoxalines, and Benzoxazoles from Primary Amines by ortho-Quinone Catalysis
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The bioinspired ortho-quinone catalysts have been applied to heterocycles synthesis. Without any metal cocatalysts, a sole ortho-quinone catalyst enables the oxidative synthesis of benzimidazoles, quinoxalines and benzoxazoles from primary amines in high yields under mild conditions with oxygen as the terminal oxidant.
- Zhang, Ruipu,Qin, Yan,Zhang, Long,Luo, Sanzhong
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supporting information
p. 5629 - 5632
(2017/10/25)
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- 6. 7 - dimethoxy - quinazoline - 4 - amine derivative, its preparation method and medical use
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The invention discloses a 6, 7-dimethoxy-quinazoline-4-amine derivative. The 6, 7-dimethoxy-quinazoline-4-amine derivative is characterized by having the following formula as shown in the specification, wherein in the formula, R1 represents hydrogen, meth
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Paragraph 0024
(2017/10/07)
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- Synthesis of benzimidazole and quinoxaline derivatives using reusable sulfonated rice husk ash (RHA-SO3H) as a green and efficient solid acid catalyst
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In this work, a simple, rapid and efficient method for the preparation of benzimidazoles and quinoxalines from the condensation of o-phenylene diamines with aldehydes and/or 1,2-dicarbonyl compounds in the presence of sulfonated rice husk ash (RHA-SO3H) as an efficient green catalyst is reported. RHA-SO3H can be easily prepared using a readily available organic compound by simple modification of rice husk ash. All reactions are performed under mild reaction conditions with high to excellent yields. The method is applicable to aromatic, unsaturated and hetero aromatic aldehydes. The advantages of this method are short reaction times, milder conditions, easy work-up, solvent-free conditions and catalyst reusability.
- Shamsi-Sani, Mahnaz,Shirini, Farhad,Abedini, Masoumeh,Seddighi, Mohadeseh
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p. 1091 - 1099
(2016/04/26)
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- CuI nanoparticles mediated expeditious synthesis of 2-substituted benzimidazoles using molecular oxygen as the oxidant
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A general and easy method for the synthesis of several 2-substituted benzimidazoles from cyclization of o-diaminobenzenes and various aldehydes using CuI nanoparticles as a heterogeneous catalyst is described. Short reaction times, easy and quick isolation of the products and excellent yields are the main advantages of this procedure. This CuI nanoparticles catalyst system was found to be air/O2 stable and also used for large scale cyclization reaction with recoverable and reusable properties without loss of catalytic activity for upto six cycles.
- Reddy, P. Linga,Arundhathi,Tripathi, Mohit,Rawat, Diwan S.
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p. 53596 - 53601
(2016/06/14)
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- Accessing Benzimidazoles via a Ring Distortion Strategy: An Oxone Mediated Tandem Reaction of 2-Aminobenzylamines
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An exceptional oxone mediated tandem transformation of 2-aminobenzylamines to 2-substituted benzimidazoles is reported. It occurs at room temperature with aromatic, heteroaromatic, and aliphatic aldehydes. In this reaction initial condensation of 2-aminobenzylamine with appropriate aldehydes afforded a tetrahydroquinazoline intermediate which underwent oxone-mediated ring distortion to afford the desired compounds in moderate to excellent yields.
- Hati, Santanu,Kumar Dutta, Pratip,Dutta, Sanjay,Munshi, Parthapratim,Sen, Subhabrata
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supporting information
p. 3090 - 3093
(2016/07/14)
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- Decarboxylative Coupling of α-Keto Acids with ortho-Phenylenediamines Promoted by an Electrochemical Method in Aqueous Media
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An electrochemical method for the decarboxylative coupling of α-keto acids with ortho-phenylenediamines was developed. The reaction proceeded smoothly in aqueous solution under air and metal catalyst-free conditions to afford 2-substituted benzimidazoles in good yields. Benzothiazoles could also be synthesized by this protocol. (Figure presented.) .
- Wang, Hai-Bin,Huang, Jing-Mei
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supporting information
p. 1975 - 1981
(2016/07/06)
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- Rapid production of benzazole derivatives by a high-pressure and high-temperature water microflow chemical process
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A high-pressure and high-temperature (HPHT) water microflow chemical process was utilized for the synthesis of benzazole derivatives. The current approach enables the extremely rapid production of various 2-arylbenzazoles including benzimidazoles, benzoxazoles, and benzthiazole in excellent yields.
- Nagao,Ishizaka,Kawanami
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supporting information
p. 3494 - 3498
(2016/07/06)
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- Iron-catalyzed highly efficient aerobic oxidative synthesis of benzimidazoles direct from oximes in water
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This article presents a general and efficient method for aerobic oxidative synthesis of benzimidazoles from oximes catalyzed by Fe(NO3)3·9H2O under air in water. This practical method uses air as an economic and green oxidant, water as a green solvent, and tolerates a wide range of substrates that can afford the target benzimidazoles in moderate to good yields.
- Yu, Jiatao,Lu, Ming
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p. 471 - 479
(2016/04/26)
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- Electrochemical Synthesis of Benzazoles from Alcohols and o-Substituted Anilines with a Catalytic Amount of CoII Salt
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An electrochemical synthesis of benzazoles directly from alcohols and o-substituted anilines has been developed. The reaction conditions have been optimized by varying the composition of the electrolyte and the metal salt used as catalyst. The cyclization proceeds smoothly with a catalytic amount of a cobalt salt under air at room temperature to afford 2-substituted benzimidazoles, benzothiazoles, and benzoxazoles in good to excellent yields with a wide substrate scope.
- Lai, Yin-Long,Ye, Jian-Shan,Huang, Jing-Mei
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supporting information
p. 5425 - 5429
(2016/04/09)
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- Catalytic Oxidative Coupling of Primary Amines under Air: A Flexible Route to Benzimidazole Derivatives
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Benzimidazoles are of fundamental importance in chemistry and biology, and the development of efficient, environmentally benign methods for their preparation remains a key challenge for organic chemists. In a biomimetic approach inspired by copper amine oxidases, we disclose herein the scope and factors influencing the success of the cooperative action of CuBr2 as electron-transfer mediator and a topaquinone-like substrate-selective catalyst in the oxidative cyclocondensation of primary amines with o-aminoanilines. This one-pot atom-economic multistep process, which works under green conditions with ambient air as the terminal oxidant, low loadings of catalyst, and equimolar amounts of commercially available amine substrates, is particularly suitable for the preparation of 1,2-disubstituted benzimidazoles. Furthermore, it allows the functionalization of nonactivated primary aliphatic amines, which are known to be challenging substrates for non-enzymatic catalytic aerobic systems.
- Nguyen, Khac Minh Huy,Largeron, Martine
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p. 1025 - 1032
(2016/03/01)
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- Aerobic oxidative synthesis of 2-arylbenzimidazoles, 2-arylbenzoxazoles, and 2-arylbenzothiazoles from arylmethanols or arylmethylamines catalyzed by Fe(III)/TEMPO under solvent-free conditions
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A simple and efficient aerobic oxidative synthesis of 2-arylbenzimidazoles, 2-arylbenzoxazoles, and 2-arylbenzothiazoles from arylmethanols or arylmethylamines with o-phenylenediamine, o-aminophenol and o-aminothiophenol catalyzed by Fe2(SO4)3/TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxyl) system under solvent-free conditions. This reaction uses air as an environmental and economic oxidant, tolerates a variety of functional groups on the aromatic ring of the benzylic partner, and affords the products in moderate yields.
- Yu, Jiatao,Shen, Mengnan,Lu, Ming
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p. 771 - 778
(2015/03/18)
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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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- Iron(III) tetranitrophthalocyanine chloride immobilized on activated carbon: Efficient, excellent chemoselectivity and recyclable catalyst for synthesis of 2-substituted benzimidazoles
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The efficient and chemoselective preparation of 2-substituted benzimidazoles was established through the coupling of o-phenylenediamine with aldehydes by using iron(III) tetranitrophthalocyanine chloride immobilized on activated carbon as efficient catalyst in ethanol at room temperature. This method tolerated a variety of functional groups and had several advantages such as environmental friendliness, ease of manipulation, and a short reaction time. In addition, this catalyst can be recovered and reused for multiple cycles without loss in its catalytic activity.
- Qiu, Jun,Zhang, Yaodu,Hua, Chengwen,Gou, Xiaofeng,Chen, Bang,Zhao, Junlong
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p. 2153 - 2162
(2015/12/12)
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- Efficient aerobic oxidative synthesis of benzimidazoles with Fe(III) based PEG1000 dicationic imidazolium ionic liquid/toluene temperature-dependent biphasic system
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A green protocol for the synthesis of benzimidazoles with Fe(III) based PEG1000 dicationic imidazolium ionic liquid ([PEG1000mim2][FeCl4]2)/toluene temperature-dependent biphasic system was described. Conformed by IR analysis, FeCl4-is the dominating anion species. It could be seen that aldehydes arylamines and aromatic aldehydes bearing electron-deficient group (-Cl,-Br,-NO2) and electron-rich groups(-OH, -N(CH3)2) on the aromatic rings gave good yields (78-96%). Moreover, the Fe(III) based PEG1000 dicationic imidazolium ionic liquid could be recycled and reused without significant loss of catalytic activity after seven runs.
- Wang, Zhao-Gang,Xia, Yong-Gen,Jin, Yong,Lu, Ming
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p. 103 - 106
(2015/04/21)
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- Highly chemoselective synthesis of benzimidazoles in Sc(OTf)3-catalyzed system
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The present researches elicit a simple, green and efficient method for the synthesis of substituted benzimidazoles through the coupling of o-phenylenediames with aldehydes catalyzed by Sc(OTf)3 in ethanol, which obtains high chemoselectivity and excellent yield of many biologically active 1,2-disubstitued and 2-substituted benzimidazoles respectively and are also environment friendly.
- Fan, Liyan,Kong, Lulu,Chen, Wen
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p. 2306 - 2314
(2016/03/01)
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- Aerobic oxidative synthesis of benzimidazoles from amines catalyzed by 3-methyl-4-oxa-5-azahomoadamantane and iron(III) chloride
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A simple and efficient catalytic system including 3-methyl-4-oxa-5- azahomoadamantane and FeCl3 for aerobic oxidative synthesis of benzimidazoles from primary amines and o-phenylenediamine is presented. This process uses O2 as economic and green oxidant and water as green solvent, tolerates a wide range of substrates, and can afford the target products in moderate to excellent yields.
- Yu, Jiatao,Lu, Ming
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p. 10017 - 10025
(2016/01/12)
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- Nano ZnO catalyzed one-pot synthesis of benzimidazoles from o-phenylenediamine with aldehydes
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Nano-ZnO was found to be a highly efficient and reusable heterogeneous catalyst for the one-pot synthesis of substituted benzimidazoles from aromatic aldehydes with o-phenylenediamine in moderate to good yield. The spent catalyst can be easily recovered and reused for five cycles with consistent activity.
- Qian, Kun,Nian, Xin,Zhu, Guan-Ming,Cui, Dong Mei,Zhang, Chen
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p. 4045 - 4048
(2015/12/23)
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- Synthesis of benzimidazoles by copper-catalyzed aerobic oxidative domino reaction of 1,2-diaminoarenes and arylmethyl halides
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Arylmethyl halides are readily synthesized via halogenation from the basic raw materials, even in green processes. They are used to replace their downstream products to prepare medicinally important 2-aryl benzimidazoles. CuBr-catalyzed synthesis of 2-aryl benzimidazoles from arylmethyl halides and 1,2-diaminoarenes via a one-pot domino reaction is developed. This new synthetic method is simple, practical and cost saving, and tolerates wide functional groups. A mechanism of CuBr-catalyzed aerobic oxidative domino reaction via a one-pot four-step process is proposed.
- Qiu, Dezhi,Wei, Haidong,Zhou, Lihong,Zeng, Qingle
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p. 109 - 112
(2014/02/14)
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- An ammonium molybdate deposited amorphous silica coated iron oxide magnetic core-shell nanocomposite for the efficient synthesis of 2-benzimidazoles using hydrogen peroxide
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An ammonium molybdate deposited amorphous silica coated iron oxide (Fe 3O4@SiO2) magnetic core-shell nanocomposite was prepared and tested in the application to the synthesis of 2-benzimidazoles from aromatic aldehydes and o-phenylenediamines using hydrogen peroxide as an oxidant at room temperature. It was found that the yields were fundamentally influenced by the nature and position of the substituents on the phenyl ring. Brunauer-Emmett-Teller (BET) analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS) confirmed that the active ammonium molybdate species are highly dispersed on the surface of the Fe3O 4@SiO2 magnetic core-shell nanocomposite, accounting for its good activity. A method was eventually developed for the synthesis of 2-benzimidazoles highlighting the good activity and easily recyclable nature of this magnetic catalyst. This journal is the Partner Organisations 2014.
- Bai, Guoyi,Lan, Xingwang,Liu, Xiaofang,Liu, Chen,Shi, Lingjuan,Chen, Qingzhi,Chen, Guofeng
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p. 3160 - 3168
(2014/06/10)
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- A green and efficient method for synthesis of benzimidazoles using nano-Fe3O4 in PEG-400/H2O aqueous system under ambient conditions at room temperature
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In this paper, a green and facile protocol was described which was efficient for synthesis of benzimidazoles using nano-Fe3O4 catalyst with continuous bubbling of air as the oxidant in PEG-400/H 2O aqueous system at room temperature. This protocol afforded the target products in good to excellent yields and the catalytic system could be recycled and reused without significant loss of catalytic activity. Copyright
- Wang, Zhao-Gang,Zhu, Jie,Zhu, Zhou-Shuo,Xu, Jian,Lu, Ming
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p. 436 - 440
(2014/06/09)
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- Aerobic photooxidative synthesis of benzimidazoles from aromatic aldehydes and diamines using catalytic amounts of magnesium iodide
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This Letter proposes a safe, mild, and environmentally benign method for the synthesis of benzimidazoles from aromatic aldehydes and diamines by aerobic photooxidation using irradiation with visible light, a catalytic amount of magnesium iodide, which serves as both a Lewis acid and an oxidant, and molecular oxygen as the terminal oxidant.
- Nagasawa, Yoshitomo,Matsusaki, Yoko,Hotta, Toshiyuki,Nobuta, Tomoya,Tada, Norihiro,Miura, Tsuyoshi,Itoh, Akichika
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p. 6543 - 6546
(2015/01/08)
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- Metal-free TEMPO-promoted C(sp3)-H amination to afford multisubstituted benzimidazoles
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An efficient TEMPO-air/cat. TEMPO-O2 oxidative protocol was developed to synthesize multisubstituted or fused tetracyclic benzimidazoles via a metal-free oxidative C-N coupling between the sp3 C-H and free N-H of readily available N1-benzyl/alkyl-1,2-phenylenediamines.
- Xue, Ding,Long, Ya-Qiu
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p. 4727 - 4734
(2014/06/09)
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- Oxidative coupling of o -phenylenediamine with arylmethylamines to synthesize aryl-substituted benzimidazoles under catalyst-free and solvent-free conditions
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GRAPHICAL ABSTRACT Solvent-free oxidative synthesis of benzimidazoles from arylmethylamines and o-phenylenediamine has been achieved under catalyst-free conditions. This reaction can use tert-butyl hydroperoxide (TBHP) as the oxidant, and a wide variety of derivatives were obtained in good yields. The reaction mechanism was proposed and this method provides a direct and practical approach for the preparation of substituted benzimidazoles.
- Yu, Jiatao,Lu, Ming
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p. 2520 - 2528
(2014/08/05)
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- Molecular iodine promoted divergent synthesis of benzimidazoles, benzothiazoles, and 2-benzyl-3-phenyl-3,4-dihydro-2H-benzo[e][1,2,4]thiadiazines
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An unprecedented formation of a new class of 2-benzyl-3-phenyl-3,4-dihydro- 2H-benzo[e][1,2,4]thiadiazines has been discovered during the course of benzimidazole and benzothiazole synthesis, through the molecular iodine-mediated oxidative cyclization with a new C-N and S-N bond formation at ambient temperature.
- Naresh, Gunaganti,Kant, Ruchir,Narender, Tadigoppula
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p. 3821 - 3829
(2014/05/20)
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- [C12mim] Br: A temperature-dependent phase transfer catalyst and its application for aerobic oxidative synthesis of 2-aryl benzimidazoles, benzoxazoles or benzothiozoles catalyzed by TEMPO based ionic liquid
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The application of [C12mim]Br ionic liquid/o-xylene temperature-dependent biphasic system into the [Imim-TEMPO][Cl]/O 2-promoted condensation between o-phenylenediamines, o-aminophenol or o-aminothiophenol with aldehydes for preparing benzimidazoles, benzoxazoles or benzothiozoles is described. Several aldehydes and o-phenylenediamines, o-aminophenol or o-aminothiophenol were reacted efficiently to form corresponding products in excellent yields. Both the [Imim-TEMPO][Cl] and [C12mim]Br could be reused at least eight times without significantly decreasing the catalytic activity. The application of [C12mim]Br ionic liquid/o-xylene temperature-dependent biphasic system into the [Imim-TEMPO][Cl]/O2-promoted condensation between o-phenylenediamines, o-aminophenol or o-aminothiophenol with aldehydes for preparing benzimidazoles, benzoxazoles or benzothiozoles is described. Several aldehydes and o-phenylenediamines, o-aminophenol or o-aminothiophenol were reacted efficiently to form corresponding products in excellent yields. Both the [Imim-TEMPO][Cl] and [C12mim]Br could be reused at least eight times without significantly decreasing the catalytic activity.
- Yu, Jiatao,Lu, Ming
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p. 578 - 582
(2014/05/20)
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- Synthesis of 2-substituted benzimidazoles using 25 % Co/Ce-ZrO2 as a heterogeneous and nanocatalyst
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25 % Co/Ce-ZrO2 nano fine particles are reported as a new catalyst for the efficient synthesis of 2-arylbenzimidazoles. A simple and convenient procedure, reusable catalyst, easy purification and shorter reaction times are the advantageous features of this method. Also prepared catalyst according to the coprecipitation method was characterized by common techniques such as SEM, XRD, FTIR and so on analysis. The catalyst is reusable and, reusable catalyst was characterized by XRD and FTIR techniques. Graphical Abstract: [Figure not available: see fulltext.]
- Behbahani, Farahnaz K.,Rezaee, Elham,Fakhroueian, Zahra
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p. 2184 - 2190
(2015/02/19)
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- Catalyst-free one-pot synthesis of benzimidazoles from 1,2-diaminoarenes and alcohols
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A new and efficient protocol is described for the one-pot synthesis of benzimidazoles from a variety of aryl alcohols and 1,2-diaminoarenes. The yields were ranging from moderate to excellent. Moreover, the present method is utilizing alcohols instead of aldehydes and the reactions are carried out under solvent- and catalyst-free conditions, offering an environmentally benign process.
- Marri, Mahender Reddy,Peraka, Swamy,Macharla, Arun Kumar,Mameda, Naresh,Kodumuri, Srujana,Nama, Narender
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supporting information
p. 6520 - 6525
(2015/01/08)
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- Iron-catalyzed highly efficient aerobic oxidative synthesis of benzimidazoles, benzoxazoles, and benzothiazoles directly from aromatic primary amines under solvent-free conditions in the open air
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Solvent-free oxidative synthesis of benzimidazoles, benzoxazoles, and benzothiazoles from aromatic primary amines and o-phenylenediamine, o-aminophenol, and o-aminothiophenol has been achieved by using Fe(NO 3)3 and TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxyl). This reaction can use air as an economical and green oxidant, and a wide variety of derivatives were obtained in good to excellent yields. The reaction mechanism was proposed and this method provides a direct, practical, and efficient approach for the preparation of substituted benzimidazoles, benzoxazoles, and benzothiazoles.
- Yu, Jiatao,Xia, Yonggen,Lu, Ming
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supporting information
p. 3019 - 3026
(2014/10/16)
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