- Preparation, characterization, and application of 1,1′-disulfo-[2,2′-bipyridine]-1,1′-diium chloride ionic liquid as an efficient catalyst for the synthesis of benzimidazole derivatives
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In this study, 2,2′-bipyridine was treated with chlorosulfonic acid and 1,1′-disulfo-[2,2′-bipyridine]-1,1′-diium chloride, [BiPy](SO3H)2Cl2, as a new ionic liquid catalyst was obtained and characterized with a variety of techniques including IR, 1H, and 13C NMR, Hammett acidity function as well as mass spectra method. After preparation and characterization, this ionic liquid was used as an efficient catalyst for the green and mild synthesis of benzimidazole derivatives. In addition, this reagent is efficiently able to catalyze the preparation of benzimidazole derivatives from the protected derivatives of aldehydes including oximes and semicarbazones. All reactions are performed under mild conditions in excellent yields.
- Shirini, Farhad,Abedini, Masoumeh,Seddighi, Mohadeseh,Arbosara, Fatemeh Shaabani
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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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- VO(acac)2 catalyzed condensation of o-phenylenediamine with aromatic carboxylic acids/aldehydes under microwave radiation affording benzimidazoles
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Vanadyl acetylacetonate, VO(acac)2, has been found to be very effective catalyst for synthesis of a variety of benzimidazoles under solvent-free condition. The methodology involves the exposure of a mixture of o-phenylenediamine and a selected aromatic carboxylic acid/aldehyde to microwave radiation without the use of any solvent or supporting agents. The benzimidazoles were obtained in quick time with high yields.
- Dey, Madhudeepa,Deb, Krishnajyoti,Dhar, Siddhartha Sankar
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- Experimental and theoretical approving of anomeric based oxidation in the preparation of 2-sbstituted benz-(imida, oxa and othia)-zoles using [2,6-DMPy-NO2]C(NO2)3 as a novel nano molten salt catalyst
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The synthesis of 2-sbstituted benz-(imida, oxa and othia)-zole derivatives were occurred in the presence of 2,6-dimethyl-1-nitropyridin-1-ium trinitromethanide [2,6-DMPy-NO2]C(NO2)3via the condensation reaction between 1,2-phenylenediamine or 2-aminophenol or 2-aminothiophenol and corresponding aldehyde at room temperature under solvent-free conditions respectively. [2,6-DMPy-NO2]C(NO2)3 as a nano molten salt (NMS) catalyst was fully characterized by Fourier transform infrared (FT-IR), nuclear magnetic resonance (1H NMR and 13C NMR), mass, thermal gravimetric (TG), derivative thermal gravimetric (DTG), X-ray diffraction patterns (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. The described reactions are in close agreement with the green chemistry disciplines and their major advantages are good yields, short reaction time and ease of separation. Our recently new introduced concept entitled "anomeric based oxidation" was proposed for the final step of the described synthesis and it was also approved using theoretical studies.
- Zolfigol, Mohammad Ali,Khazaei, Ardeshir,Alaie, Saied,Baghery, Saeed,Maleki, Farahnaz,Bayat, Yadollah,Asgari, Asiye
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- UV-visible light-induced photochemical synthesis of benzimidazoles by coomassie brilliant blue coated on W-ZnO@NH2nanoparticles
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Heterogeneous photocatalysts proffer a promising method to actualize eco-friendly and green organic transformations. Herein, a new photochemical-based methodology is disclosed in the preparation of a wide range of benzimidazoles through condensation of o-phenylenediamine with benzyl alcohols in the air under the illumination of an HP mercury lamp in the absence of any oxidizing species catalyzed by a new photocatalyst W-ZnO@NH2-CBB. In this photocatalyst, coomassie brilliant blue (CBB) is heterogenized onto W-ZnO@NH2 to improve the surface characteristics at the molecular level and enhance the photocatalytic activity of both W-ZnO@NH2 and CBB fragments. This unprecedented heterogeneous nanocatalyst is also identified by means of XRD, FT-IR, EDS, TGA-DTG, and SEM. The impact of some influencing parameters on the synthesis route and effects on the catalytic efficacy of W-ZnO@NH2-CBB are also assessed. The appropriate products are attained for both the electron-withdrawing and electron-donating substituents in the utilized aromatic alcohols. Furthermore, preparation of benzimidazoles is demonstrated to occur mainly via a radical mechanism, which shows that reactive species such as ·O2-, OH and h+ would be involved in the photocatalytic process. Stability and reusability studies also warrant good reproducibility of the nanophotocatalyst for at least five runs. Eventually, a hot filtration test proved that the nanohybrid photocatalyst is stable in the reaction medium. Using an inexpensive catalyst, UV-vis light energy and air, as a low cost and plentiful oxidant, puts this methodology in the green chemistry domain and energy-saving organic synthesis strategies. Finally, the anticancer activity of W-ZnO nanoparticles is investigated on MCF7 breast cancer cells by MTT assay. This experiment reveals that the mentioned nanoparticles have significant cytotoxicity towards the selected cell line.
- Chen, Ruijuan,Jalili, Zahra,Tayebee, Reza
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- Efficient copper-catalyzed synthesis of 2-arylbenzimidazole derivatives by reaction of 1-fluoro-2-nitrobenzene with benzamidine hydrochlorides
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[Figure not available: see fulltext.] A novel and efficient approach to the preparation of 2-arylbenzimidazoles is described. Heating a mixture of 1-fluoro-2-nitrobenzene and benzamidine hydrochlorides in the presence of CuBr and K2CO3/su
- Sayahi, Mohammad Hosein,Khoshneviszadeh, Mehdi,Soheilizad, Mehdi,Saghanezhad, Seyyed Jafar,Mahdavi, Mohammad
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- One-pot synthesis of benzoazoles via dehydrogenative coupling of aromatic 1,2-diamines/2-aminothiophenol and alcohols using Pd/Cu-MOF as a recyclable heterogeneous catalyst
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In this paper we report an efficient synthetic approach for the preparation of the widespread numbers of benzoazoles via dehydrogenative coupling of 1,2-phenylenediamine or 2-aminothiophenol and benzyl alcohols by Pd/Cu2(BDC)2(DABCO)-MOF as new heterogeneous catalyst under solvent-free condition. The catalyst recycled and reused for four times without loss of catalytic activity. The structures of benzoazoles were corroborated spectroscopically (1H- and 13C NMR, and elemental analysis) and were confirmed by comparison with reference compounds. A plausible mechanism for this type of reaction is proposed.
- Mokhtari, Javad,Hasani Bozcheloei, Abolfazl
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- Synergic effect of copper-based metal-organic frameworks for highly efficient C-H activation of amidines
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A Cu-MOF-catalyzed C-H functionalization of substituted amidines was developed for the facile and efficient synthesis of benzimidazoles. More importantly, this transformation is compatible with various substrates derived from aryl nitriles without ortho substituents. Under reaction conditions devoid of O2 atmosphere or specific groups, 537-MOF has been revealed as a key parameter for expanding the reaction scope and increasing the yield up to 96%. Importantly, this strategy also provides numerous opportunities for further utilization of MOFs as catalysts for challenging organic reactions.
- Xu, Fen,Kang, Wei-Fen,Wang, Xiao-Ning,Kou, Hao-Dong,Jin, Zhen,Liu, Chun-Sen
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- Microwave irradiation synthesis of 2-substituted benzimidazoles using PPA as a catalyst under solvent-free conditions
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An efficient microwave irradiation synthesis of 2-substituted benzimidazoles using polyphosphoric acid (PPA) as a catalyst from organic acid and o-phenylenediamine under solvent-free conditions is described. This method is a good option to obtain the title compounds in a simple and an inexpensive way.
- Lu, Jun,Yang, Bingqin,Bai, Yinjuan
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- Cu–S-(propyl)-2-aminobenzothioate on magnetic nanoparticles: highly efficient and reusable catalyst for synthesis of polyhydroquinoline derivatives and oxidation of sulfides
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Cu–S-(propyl)-2-aminobenzothioate supported on functionalized Fe3O4 magnetic nanoparticles is reported as a reusable and highly efficient nanocatalyst for the one-pot synthesis of polyhydroquinoline derivatives and also for selective
- Ghorbani-Choghamarani, Arash,Tahmasbi, Bahman,Moradi, Parisa,Havasi, Nasrin
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- Green and efficient methods for one-pot aerobic oxidative synthesis of benzimidazoles from alcohols with TEMPO-PEG 4000-NHC-Cu(II) complex in water
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In this article, an amphiphilic catalyst TEMPO-PEG4000-NHC-Cu(II) [2,2,6,6-tetramethylpiperidine-1-oxyl/polyethylene glycol/N-heterocyclic carbene] complex was synthesized and used as a highly efficient catalyst for one-pot aerobic oxidative synthesis of benzimidazoles from alcohols. The reactions were applicable in water with good yields in the presence of catalyst (5 mol%). Moreover, the catalyst was easily recovered from the reaction mixture and reused with almost consistent activity.
- Wang, Zhao-Gang,Cao, Xiao-Hua,Yang, Yao,Lu, Ming
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- Synthesis of benzimidazoles by two methods (C–H functionalization and condensation reaction) catalyzed by α-zirconium hydrogen phosphate-based nanocatalyst
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In this report, two heterogeneous nanocatalysts based on α-zirconium hydrogen phosphate were applied. These heterogeneous catalysts have demonstrated the promising catalytic activity for the synthesis of 2-substituted benzimidazoles in two different methods. One of these reactions is the functionalization of the C–H bond and the formation of C–N bond, and the other reaction involves the condensation reaction between aldehydes and 1,2-phenylenediamine. The activity of both catalysts was compared in two methods, and the superior catalyst was introduced. The prepared catalysts are easily separated from the reaction mixture by centrifugation and reused several times without significant loss of activity.
- Hajipour, Abdol R.,Zakery, Saedeh,Khorsandi, Zahra
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- Eco-friendly synthesis of benzimidazole derivatives using solid acid scolecite catalyst
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A series of benzimidazole derivatives were synthesized expeditiously in good yields by condensation of 1,2-diaminobenzene and aromatic aldehydes in the presence of modified scolecite catalyst. The world wide availability, easy handling and reusability of catalyst, higher yields and shorter reaction times are the advantages of the present method.
- Gadekar, Lakshman S.,Arbad, Balasaheb R.,Lande, Machhindra K.
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- A fast procedure for the preparation of benzimidazole derivatives using polymer-supported with trifluoromethanesulfonic acid as novel and reusable catalyst
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A highly selective synthesis of benzimidazoles from the reaction of o-phenylenediamines and aromatic aldehydes in the presence of PVP- trifluoromethanesulfonic acid is reported, and morphological investigation was reported by FT-IR. The remarkable advanta
- Karami, Changiz,Ghodrati, Keivan,Izadi, Mina,Farrokh, Azita,Jafari, Sedigheh,Mahmoudiyani, Maryam,Haghnazari, Nahid
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- Copper-catalyzed intramolecular C-N bond formation: A straightforward synthesis of benzimidazole derivatives in water
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A straightforward, efficient, and more sustainable copper-catalyzed method has been developed for intramolecular N-arylation providing the benzimidazole ring system. With Cu2O (5 mol %) as the catalyst, DMEDA (10 mol %) as the ligand, and K2CO3 as the base, this protocol was applied to synthesize a small library of benzimidazoles in high yields. Remarkably, the reaction was exclusively carried out in water, rendering the methodology highly valuable from both environmental and economical points of view.
- Peng, Jinsong,Ye, Min,Zong, Cuijuan,Hu, Fangyun,Feng, Lingtong,Wang, Xiaoyan,Wang, Yufeng,Chen, Chunxia
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- H2 Activation with Co Nanoparticles Encapsulated in N-Doped Carbon Nanotubes for Green Synthesis of Benzimidazoles
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Co nanoparticles (NPs) encapsulated in N-doped carbon nanotubes (Co@NC900) are systematically investigated as a potential alternative to precious Pt-group catalysts for hydrogenative heterocyclization reactions. Co@NC900 can efficiently catalyze hydrogenative coupling of 2-nitroaniline to benzaldehyde for synthesis of 2-phenyl-1H-benzo[d]imidazole with >99 % yield at ambient temperature in one step. The robust Co@NC900 catalyst can be easily recovered by an external magnetic field after the reaction and readily recycled for at least six times without any evident decrease in activity. Kinetic experiments indicate that Co@NC900-promoted hydrogenation is the rate-determining step with a total apparent activation energy of 41±1 kJ mol?1. Theoretical investigations further reveal that Co@NC900 can activate both H2 and the nitro group of 2-nitroaniline. The observed energy barrier for H2 dissociation is only 2.70 eV in the rate-determining step, owing to the presence of confined Co NPs in Co@NC900. Potential industrial application of the earth-abundant and non-noble transition metal catalysts is also explored for green and efficient synthesis of heterocyclic compounds.
- Lin, Chuncheng,Wan, Weihao,Wei, Xueting,Chen, Jinzhu
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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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- Comparative studies on conventional and microwave assisted synthesis of benzimidazole and their 2-substituted derivative with the effect of salt form of reactant
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Benzimidazole and their derivative were reported to have wide biological activities and were synthesized by using different solvents and ring closing agents. The present work deals with the comparative synthesis of 2-alkyl and aryl substituted benzimidazole derivative in the presence of polyphosphoric acid through microwave and conventional methods and also studied the effect of salt form of reactant for completion of the reaction. The 2-substituted aryl and alkyl benzimidazole derivative were synthesized via microwave and was observed to be more beneficial, in respect of yield (increases up to 10 to 50%) and time (96 to 98% was reduced) than conventional method of synthesis. This study was concluded that the salt form of reactant (o-phenylenediamine dihydrochloride) gave reduced colour impurities, homogenous mixing and reduced time for completion of reaction.
- Dubey, Raghvendra,Hari Narayana Moorthy, Narayana Subbiah
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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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- A rapid and efficient synthesis of benzimidazoles using hypervalent iodine as oxidant
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Various 2-arylbenzimidazoles were synthesized from phenylenediamines and aldehydes via a one-step process using hypervalent iodine as an oxidant. The salient features of this method include mild conditions, short reaction times (3-5 min), high yields, and simple procedure. Georg Thieme Verlag Stuttgart.
- Du, Li-Hua,Wang, Yan-Guang
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- An unexpected role of carbon disulfide: A new and efficient method for the synthesis of 2-substituted benzimidazoles
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A new and efficient methodology for the synthesis of 2-substituted benzimidazoles is described. In this procedure, CS2 unexpectedly facilitated the cyclization reaction between benzene-1,2-diamine and benzenecarbaldehydes in CH2Clsu
- Gladysz, John A.,Safaei, Hamid Reza,Nouri, Sara
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- Benzoyl methyl phosphates as efficient reagents in the one-pot tandem approach for the synthesis of 2-phenylbenzimidazoles in water
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A novel and efficient method for the environmentally benign, catalyst- and auxiliary-free synthesis of 2-phenylbenzimidazoles in water is developed. Benzoyl methyl phosphates play important roles as biomimetic acylating agents for the one-pot tandem approach without additional catalysts.
- Hikawa, Hidemasa,Imani, Maki,Suzuki, Hideharu,Yokoyama, Yuusaku,Azumaya, Isao
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- Nanoparticle mediated organic synthesis (NAMO-synthesis): CuI-NP catalyzed ligand free amidation of aryl halides
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The first CuI-nanoparticle catalyzed ligand free synthesis of N-aryl amides from aryl halides and arylamides/cyclic amides has been developed. This methodology is further extended for the synthesis of nitrogen heterocycles such as benzimidazole, and quinazolinone via intermolecular amidation reaction followed by cyclization. TEM images of the CuI-NP catalyst showed spherical, well-dispersed particles which provide large surface area for reactivity and have good recyclability. This journal is
- Kumar, Atul,Bishnoi, Ajay Kumar
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- Air-stable Ruthenium(II)-NNN Pincer Complexes for the Efficient Coupling of Aromatic Diamines and Alcohols to 1H-benzo[d]imidazoles with the Liberation of H2
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Two new phosphine-free RuII-NNN pincer complexes ([RuCl(L1)(CH3CN)2]Cl (1) and [RuCl(L2)(CH3CN)2]Cl (2) [L1=2,6-bis(1H-imidazole-2-yl)pyridine, L2=2,6-bis(1-hexyl-1H-imidazole-2-yl)pyridine] were synthesized to catalyze the condensation of benzyl alcohol and benzene-1,2-diamine homogeneously to 2-pheny-1H-benzo[d]imidazole and H2. The reactivity in the order of 1>2 is lower than that of the phosphine-containing RuII-NNN pincer complex [RuCl2(L1)(PPh3)3] (3), and thus a homogeneous system that contained 1, 1 equivalent of 1,2-bis(diphenylphosphanyl)ethane, and 10 equivalents of NaBPh4 was developed to improve the catalytic efficiency for the condensation of primary alcohols and benzene-1,2-diamine (or its derivatives) to 2-substituted 1H-benzo[d]imidazoles in excellent yields (up to 97 %) and turnover numbers (388). This system can be used to realize the facile one-step synthesis of 1H-benzo[d]imidazole derivatives from alcohols without the use of an oxidant and/or a stoichiometric amount of inorganic base that is usually necessary in homogeneous systems reported previously.
- Li, Lin,Luo, Qi,Cui, Huahua,Li, Renjie,Zhang, Jing,Peng, Tianyou
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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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- Synthesis of 2-arylbenzimidazoles in microfluidic chip reactor
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A simple and efficient continuous flow synthesis of 2-arylbenzimidazoles from phenylenediamines and aromatic aldehydes in the presence of iodobenzene diacetate (IBD) has been developed by using a microfluidic chip reactor system. Various substituted 2-ary
- Lei, Ming,Li, Wei,Hu, Ruijun,Tian, Wan,Wang, Yanguang,Zhang, Hong
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- Isocyanurate-based periodic mesoporous organosilica (PMO-ICS): A highly efficient and recoverable nanocatalyst for the one-pot synthesis of substituted imidazoles and benzimidazoles
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Isocyanurate bridging periodic mesoporous organosilica (PMO-ICS) was shown to be a highly active and efficient recyclable catalyst for the three-component synthesis of imidazole derivatives from benzoin, different aldehydes and ammonium acetate under mild reaction conditions in short reaction times and good to excellent yields in EtOH. Also, benzimidazole derivatives were efficiently prepared from o-phenylenediamine and different aldehydes in the presence of PMO-ICS. Moreover, the catalyst was also recovered and reused at least four times without a significant decrease in its activity. The PMO-ICS catalyst was characterized by Fourier transformer infrared (FTIR) spectroscopy, thermogravimetry analysis (TGA), powder X-ray diffraction (XRD) and nitrogen adsorption-desorption isotherm (NADI) techniques as well as field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Compared to the classical methodologies, this method illustrated significant advantages including low loading of the catalyst, avoiding the use of toxic transition metals or reactive reagents for modification of the catalytic activity, short reaction times, high to excellent yields, easy separation and purification of the products, and reusability of the catalyst.
- Dekamin, Mohammad G.,Arefi, Elham,Yaghoubi, Amene
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- Catalytic Performance of Hydrophobic Sulfonated Nanocatalysts CMK-5-SO3H and SBA-15-Ph-PrSO3H for Ecofriendly Synthesis of 2-Substituted Benzimidazoles in Water
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The hydrophobicity of environmentally benign organosulfonic acid-functionalized silica (SBA-15-Ph-PrSO3H) and sulfonic acid-based nanoporous carbon (CMK-5-SO3H) was assessed in relation to the green synthesis of 2-substituted benzimidazoles from aldehydes and benzene-1,2-diamine in open air in an aqueous medium. The results are rationalized in terms of the inclusion of the substrates inside hydrophobic cavities of the catalysts. Furthermore, the more hydrophobic and more water-resistant catalyst CMK-5-SO3H showed superior catalytic activity. Their excellent yields, their use of water as a green solvent, and their recyclability and environmentally friendly nature makes these catalysts important alternatives to classical acid catalysts.
- Zareyee, Daryoush,Rostamian Tuyehdarvary, Sakineh,Allahgholipour, Leila,Hossaini, Zinatossadat,Khalilzadeh, Mohammad A.
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- Metallovesicles as smart nanoreactors for green catalytic synthesis of benzimidazole derivatives in water
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Metallovesicles are an emerging class of soft nanomaterials where spherical bilayer membranes, resulting from self-aggregation of amphiphilic metal complexes, amalgamate the advantages of metal specific catalytic properties and small hydrophobic cavities
- Kaur, Navneet,Kaur, Simranpreet,Kaur, Gurpreet,Bhalla, Aman,Srinivasan, Sesha,Chaudhary, Ganga Ram
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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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- An efficient and reusable heterogeneous catalyst Animal Bone Meal for facile synthesis of benzimidazoles, benzoxazoles, and benzothiazoles
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A library of benzimidazoles, benzoxazoles, and benzothiazoles was efficiently synthesized by condensation of o-phenylenediamine, o-aminophenol, and o-aminothiophenol respectively with aromatic aldehydes in the presence of catalytic amounts of Animal Bone Meal (ABM) and Lewis acids doped ABMs. Reactions were conducted under reflux conditions in air. The remarkable features of this new protocol are high conversion, short reaction times, and cleaner reaction profiles, straightforward procedure, and reduction in catalyst toxicity.
- Riadi, Yassin,Mamouni, Rachid,Azzalou, Rachid,Haddad, Mohammadine El,Routier, Sylvain,Guillaumet, Gérald,Lazar, Sa?d
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- Copper nanoparticles loaded polymer vesicles as environmentally amicable nanoreactors: A sustainable approach for cascading synthesis of benzimidazole
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This paper reports the synthesis and characterization of Cu nanoparticle loaded, surfactant free metallovesicles (CuNPs@vesicles) as nanoreactors to produce benzimidazoles via cascade reaction. The vesicles exhibited uniform size distribution, spherical m
- Shukla, Falguni,Das, Manita,Thakore, Sonal
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- Synthesis of 2-substituted benzimidazoles and benzothiazoles using Ag2CO3/Celite as an efficient solid catalyst
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An efficient and simple approach for the synthesis of 2-substituted benzimidazoles and benzothiazoles through a coupling of 1,2-phenylenediamines and 2-aminothiophenols with variety of aryl aldehydes in ethanol at 70 °C using Ag2CO3/Celite as solid catalyst is described. The procedure features short reaction time, excellent yields and simple workup.
- Soleimani, Ebrahim,Khodaei, Mohammad Mehdi,Yazdani, Hossein,Saei, Parisa,Zavar Reza, Javad
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- One-pot synthesis of benzimidazoles by simultaneous photocatalytic and catalytic reactions on Pt@TiO2 nanoparticles
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"Chemical Equation Presented" Dual platinum action: A one-pot catalytic synthesis of benzimidazoles from the photoirradiation of an alcohol solution containing an ortho-arylenediamine and Pt@TiO2 nanoparticles is described. This reaction proceeded by the platinumassisted photocatalytic oxidation of an alcohol and a catalytic dehydrogenation of the intermediates on the surface of platinum nanoparticles.
- Shiraishi, Yasuhiro,Sugano, Yoshitsune,Tanaka, Shunsuke,Hirai, Takayuki
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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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- Selective autoxidation of benzylamines: Application to the synthesis of some nitrogen heterocycles
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A green and remarkably simple synthesis of nitrogen heterocycles from benzylamines and anilines o-substituted by a cyclizable group has been developed based on selective uncatalyzed autoxidation of benzylamines.
- Nguyen, Thanh Binh,Ermolenko, Ludmila,Al-Mourabit, Ali
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- Zirconocene catalyzed synthesis of 2-substituted benzimidazole derivatives
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Abstract: Zirconocene dichloride (Cp2ZrCl2) in the presence of ethanol is found to be a highly efficient catalyst for the one-pot synthesis of structurally diverse 2-substituted benzimidazole derivatives by reaction of o-phenylenedia
- Karhale, Shrikrishna,Patil, Kiran,Bhenki, Chandrakant,Rashinkar, Gajanan,Helavi, Vasant
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- [Diaquo{bis(p-hydroxybenzoato-κ1O1)}(1-methylimidazole- κ1N1)}copper(II)]: Synthesis, crystal structure, catalytic activity and DFT study
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Metal-organic hybrid complexes often exhibit large surface area, pore volume, fascinating structures and potential applications including catalytic applications. Hence a new metal-organic hybrid complex [Diaquo{bis(p-hydroxybenzoato-κ1O1)}(1-methylimidazole- κ1N1)}copper(II)] was synthesized using conventional method. Physico-chemical characterization of the complex was performed with FTIR spectroscopy, single crystal X-ray diffraction, TGA, EPR and FESEM. Single crystal X-ray diffraction study suggests it to be three dimensional with space group P212121 (orthorhombic). The crystal achieves its three-dimensional structure and stability through extensive intermolecular hydrogen bonding. Hirshfeld surface analysis, catalytic activity and DFT study of the complex was also performed. The synthesized complex acts as good catalyst in benzimidazole synthesis with good recyclability as catalyst up to 5th run.
- Brahman, Dhiraj,Chhetri, Sailesh,Kamath, Amarjit,McArdle, Patrick,Sinha, Biswajit
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- Redox-Neutral Photocatalytic Radical Cascade Cyclization for the Synthesis of CH2CN/CF2COOEt/CF3-Containing Benzo[4,5]imidazo[2,1-a]isoquinolin-6(5 H)-One Derivatives
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A novel method for the synthesis of benzo[4,5]imidazo[2,1-A]isoquinolin derivatives via visible-light-induced radical cascade cyclization is described. By using N-methacryloyl-2-phenylbenzoimidazoles and diverse radical precursors, various benzo[4,5]imidazo[2,1-A]isoquinolin derivatives containing CH2CN/CF2COOEt/CF3 can be formed in good to excellent yields under mild reaction conditions. This method exhibits good functional group tolerance and a wide range of substrate scope.
- Liu, Liang,Yang, De-Yong,He, Yan-Hong,Guan, Zhi
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- BiOCl/FeOCl/SiO2 nanocomposite as an efficient novel catalyst toward the synthesis of 2-aryl-1hbenzimidazoles in mild aerobic condition
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BiOCl/FeOCl nanorods composited by SiO2 spherical nanoparticles as a novel nanocatalyst and also it has been synthesized using a co-precipitation procedure. Additionally, its structural along with the catalyst activity have been determined by t
- Mohammadi, Hadi,Karami, Changiz,Bahri, Mahboobeh,Gilany, Marayam Mahmoudian,Taher, Mohammad Ali
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- Ytterbium perfluorooctanesulfonates catalyzed synthesis of benzimidazole derivatives in fluorous solvents
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Catalytic condensation of o-phenylenediamine and aldehydes was accomplished using rare earth(III)perfluorooctane sulfonates (RE(OPf)3), RE = Sc, Y, La ~ Lu) as catalysts in fluorous solvents. Ytterbium perfluorooctanesulfonates (Yb(OPf)3) catalyzes the high-efficient synthesis of benzimidazole derivatives in fluorous solvents. By simple separation, fluorous phase containing only catalyst can be reused several times.
- Shen, Ming-Gui,Cai, Chun
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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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- Construction of Benzimidazoles and Benzoxazoles through the Molybdenum-Mediated Carbonylation of Aryl Halides
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The facile and efficient one-pot construction of benzimidazoles and benzoxazoles through the Mo(CO)6-mediated carbonylation of aryl halides was examined. In the process, Mo(CO)6 acted as a convenient and safe solid source of carbon monoxide. A wide range of substrates were tolerated to provide the corresponding products in fair to good yields without the need of gaseous CO or palladium catalysts. The facile and efficient one-pot construction of benzimidazoles and benzoxazoles is described. The reaction proceeds through Mo(CO)6-mediated carbonylation of aryl halides, in which Mo(CO)6 acts as a convenient and safe solid source of carbon monoxide.
- Kebede, Eshetu,Tadikonda, Ramu,Nakka, Mangarao,Inkollu, Bhargavi,Vidavalur, Siddaiah
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- Ionic liquid-immobilized hybrid nanomaterial: an efficient catalyst in the synthesis of benzimidazoles and benzothiazoles via anomeric-based oxidation
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Abstract: In this study, a novel ionic liquid immobilized on silica-coated cobalt-ferrite magnetic nanoparticles. This novel hybrid nanostructure (CoFe2O4@SiO2@PAF-IL) was characterized by various microscopic and spectroscopic techniques including Fourier transformation infrared spectroscopy (FT–IR), X-ray powder diffraction (XRD), field emission scanning electron microscopy (SEM), the electron-dispersive X-ray spectroscopy (EDS), vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA/DTG). The catalytic activity of prepared nanomaterial was considered in the synthesis of the benzothiazole and benzimidazole derivatives. This method has several advantages such as good to excellent yields, short reaction times, solvent-free and environmentally-benign conditions, and simple work-up. Besides, nanocatalyst can be easily separated from the reaction mixture with the external magnetic field and reused several times without any loss of its catalytic activity. Graphic abstract: [Figure not available: see fulltext.].
- Bodaghifard, Mohammad Ali,Shafi, Saeideh
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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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- BENZIMIDAZOLE REARRANGEMENT OF DIHYDROBENZODIAZEPINES
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The rearrangements of 2,4-diphenyl-2,3-dihydro-1H-1,5-benzodiazepines under the influence of acids, temperature, and electron impact were studied.It is shown that the trend of the process is strictly specific for each case.The mechanism and the factors that regulate the trend of the benzimidazole rearrangement are discussed.
- Orlov, V. D.,Kolos, N. N.,Zolotarev, B. M.
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- Synthesis of 1,2-disubstituted benzimidazoles, 2-substituted benzimidazoles and 2-substituted benzothiazoles in SDS micelles
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A practical and convenient synthetic method has been developed for the facile synthesis of 1,2-disubstituted benzimidazoles, 2-substituted benzimidazoles and 2-substituted benzothiazoles. The method described has the benefits of operational simplicity, excellent yields, and high chemoselectivity. The Royal Society of Chemistry 2010.
- Bahrami, Kiumars,Khodaei, Mohammad M.,Nejati, Akbar
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- Microwave assisted aqueous phase synthesis of benzothiazoles and benzimidazoles in the presence of Ag2O
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A simple and high yielding method for synthesized benzothiazoles and benzimidazole in water under micro wave irradiation by the reaction of 2-amino thiophenol and o-phenylenediamine with various aromatic aldehydes in the presence of Ag2O. Agsu
- Sakram,Rambabu,Ashok,Sonyanaik,Ravi
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- Synthesis, bioevaluation and docking studies of some 2-phenyl-1H-benzimidazole derivatives as anthelminthic agents against the nematode Teladorsagia circumcincta
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Gastrointestinal nematode infections are the main diseases in herds of small ruminants. Resistance to the main established drugs has become a worldwide problem. The purpose of this study is to obtain and evaluate the in vitro ovicidal and larvicidal activity of some 2-phenylbenzimidazole derivatives on susceptible and resistant strains of Teladorsagia circumcincta. Compounds were prepared by known procedures from substituted o-phenylenediamines and arylaldehydes or intermediate sodium 1-hydroxyphenylmethanesulfonate derivatives. Egg Hatch Test (EHT), Larval Mortality Test (LMT) and Larval Migration Inhibition Test (LMIT) were used in the initial screening of compounds at 50 μM concentration, and EC50 values were determined for the most potent compounds. Cytotoxicity evaluation of compounds was conducted on human Caco-2 and HepG2 cell lines to calculate their Selectivity Indexes (SI). At 50 μM concentration, nine out of twenty-four compounds displayed more than 98% ovicidal activity on a susceptible strain, and four of them showed more than 86% on one resistant strain. The most potent ovicidal benzimidazole (BZ) 3 showed EC50 = 6.30 μM, for the susceptible strain, while BZ 2 showed the lowest EC50 value of 14.5 μM for the resistant strain. Docking studies of most potent compounds in a modelled Teladorsagia tubulin indicated an inverted orientation for BZ 1 in the colchicine binding site, probably due to its fair interaction with glutamic acid at codon 198, which could justify its inactivity against the resistant strain of T. circumcincta.
- Escala, Nerea,Valderas-García, Elora,Bardón, María álvarez,Gómez de Agüero, Verónica Castilla,Escarcena, Ricardo,López-Pérez, José Luis,Rojo-Vázquez, Francisco A.,San Feliciano, Arturo,Bala?a-Fouce, Rafael,Martínez-Valladares, María,Olmo, Esther del
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- Nanoporous Cu doped ZnS nanoparticles an efficient photo catalyst for the chemoselective synthesis of 2-substituted azoles via C-N arylation/ CSp3– H oxidation/ cyclization/dehydration sequence in visible light
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ZnS and Cu:ZnS nanoparticles were prepared by aqueous chemical method and characterized by several analytical tools. Nanoparticles have an average size of about ~ 18 nm and possess highly open mesopores, moderate surface area, and uniform morphology. UV–vis spectra designate that doping of Cu shifted the optical response of the ZnS nanoparticles in to a visible region. These Cu:ZnS nanoparticles were employed as a photocatalyst for chemoselective synthesis of 2-substituted azoles by the reaction of benzyl bromides and 1,2-Diaminobenzene or 2-Mercaptoaniline in visible light. Analogous experiments confirmed that the reaction were proceeds through one pot C–N arylation/ CSp3– H oxidation/ cyclization/dehydration sequence. The enhanced catalytic activity by doping could be attributed to the presence of trapping level generated by copper doping which augments the relaxation time of electron and holes so that they are easily available for the reaction. The method was also applicable for the synthesis of quinazolin-4(3H)-ones.
- Dandia, Anshu,Bansal, Sarika,Sharma, Ruchi,Kumar Mahawar, Dinesh,Rathore, Kuldeep S.,Lal Meena, Mohan,Parewa, Vijay
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- An Unexpected Formation of 2-Arylbenzimidazoles from α,α-Diiodo-α’-acetoxyketones and o-Phenylenediamines
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An unusual reactivity of the α,α-diiodo-α’-acetoxyketones with o-phenylenediamines is reported through the formation of 2-arylbenzimidazoles. A systematic study through a series of fruitful control experiments and isolation of key intermediates unravelled the unprecedented domino mechanism. This process involves a stepwise two-carbon fragmentation pathway through domino and sequential amidation–aziridination–decarbonylation–I2-mediated aminative cyclization–oxidation reactions. This strategy employs no additives like oxidant, metal catalyst, bases, and represents yet another novel reactivity profile of the building blocks α,α-diiodo-α’-acetoxyketones.
- Sadhukhan, Santu,Mondal, Swagata,Baire, Beeraiah
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- Solvent-dependent metal-free chemoselective synthesis of benzimidazoles and 1,3,5-triarylbenzenes from 2-amino anilines and aryl alkyl ketones catalyzed by I2
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A solvent-dependent I2-catalyzed chemoselective reaction was developed for the synthesis of benzimidazoles and 1,3,5-triarylbenzenes via the annulation of 2-amino anilines and aryl alkyl ketones or the cyclization of aryl alkyl ketones, respectively. With 1,4-dioxane as the solvent, sequential C[sbnd]N bond formation followed by C(CO)-C(CH3) bond cleavage leads to the formation of benzimidazoles in a highly selective manner while aldol-type self-condensation of aryl alkyl ketones predominates using PhNO2 or PhCl as the solvent to afford 1,3,5-triarylbenzenes.
- Ding, Yuxin,Ma, Renchao,Ma, Yongmin
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supporting information
(2021/04/09)
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- A TEMPO-Functionalized Ordered Mesoporous Polymer as a Highly Active and Reusable Organocatalyst
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The properties of high stability, periodic porosity, and tunable nature of ordered mesoporous polymers make these materials ideal catalytic nanoreactors. However, their application in organocatalysis has been rarely explored. We report herein for the first time the incorporation of a versatile organocatalyst, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), into the pores of an FDU-type mesoporous polymer via a pore surface engineering strategy. The resulting FDU-15-TEMPO possesses a highly ordered mesoporous organic framework and enhanced stability, and shows excellent catalytic activity in the selective oxidation of alcohols and aerobic oxidative synthesis of 2-substituted benzoxazoles, benzimidazoles and benzothiazoles. Moreover, the catalyst can be easily recovered and reused for up to 7 consecutive cycles.
- Guo, Ying,Wang, Wei David,Li, Shengyu,Zhu, Yin,Wang, Xiaoyu,Liu, Xiao,Zhang, Yuan
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p. 3689 - 3694
(2021/09/29)
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- Nickel catalyzed sustainable synthesis of benzazoles and purines: Via acceptorless dehydrogenative coupling and borrowing hydrogen approach
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Herein we report nickel-catalyzed sustainable synthesis of a few chosen five-membered fused nitrogen heterocycles such as benzimidazole, purine, benzothiazole, and benzoxazole via acceptorless dehydrogenative functionalization of alcohols. Using a bench stable, easy to prepare, and inexpensive Ni(ii)-catalyst, [Ni(MeTAA)] (1a), featuring a tetraaza macrocyclic ligand (tetramethyltetraaza[14]annulene (MeTAA)), a wide variety of polysubstituted benzimidazole, purine, benzothiazole, and benzoxazole derivatives were prepared via dehydrogenative coupling of alcohols with 1,2-diaminobenzene, 4,5-diaminopyrimidine, 2-aminothiphenol, and 2-aminophenol, respectively. A wide array of benzimidazoles were also prepared via a borrowing hydrogen approach involving alcohols as hydrogen donors and 2-nitroanilines as hydrogen acceptors. A few control experiments were performed to understand the reaction mechanism.
- Chakraborty, Gargi,Guin, Amit Kumar,Mondal, Rakesh,Paul, Nanda
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p. 7217 - 7233
(2021/08/30)
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- Transition-Metal-Free Transfer Hydrogenative Cascade Reaction of Nitroarenes with Amines/Alcohols: Redox-Economical Access to Benzimidazoles
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This report describes an efficient transition-metal-free process toward the transfer hydrogenative cascade reaction between nitroarenes and amines or alcohols. The developed redox-economical approach was realized using a combination of KOtBu and Et3SiH as reagents, which allows the synthesis of benzimidazole derivatives via σ-bond metathesis. The reaction conditions hold well over a wide range of substrates embedded with diverse functional groups to deliver the desired products in good to excellent yields. The mechanistic proposal has been depicted on the basis of a series of control experiments, mass spectroscopic evidence which is well supported by density functional theory (DFT) calculations with a feasible energy profile.
- Gujjarappa, Raghuram,Kabi, Arup K.,Malakar, Chandi C.,Musib, Dulal,Roy, Anupam,Sahoo, Abhishek,Singh, Virender,Vodnala, Nagaraju
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p. 14597 - 14607
(2021/11/12)
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- 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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- Ionic-Liquid-Catalyzed Synthesis of Imines, Benzimidazoles, Benzothiazoles, Quinoxalines and Quinolines through C?N, C?S, and C?C Bond Formation
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We report the tetramethyl ammonium hydroxide catalyzed oxidative coupling of amines and alcohols for the synthesis of imines under metal-free conditions by utilizing oxygen from air as the terminal oxidant. Under the same conditions, with ortho-phenylene diamines and 2-aminobenzenethiols the corresponding benzimidazoles and benzothiazoles were obtained. Quinoxalines were obtained from ortho-phenylene diamines and 1-phenylethane-1,2-diol, the conditions were then extended to the synthesis of quinoline building blocks by reaction of 2-amino benzyl alcohols either with 1-phenylethan-1-ol or acetophenone derivatives. The formation of C?N, C?S and C?C bonds was achieved under metal-free conditions. A broad range of amines (aromatic, aliphatic, cyclic and heteroaromatic) as well as benzylic alcohols including heteroaryl alcohols reacted smoothly and provided the desired products. The mild reaction conditions, commercially available catalyst, metal-free, good functional-group tolerance, broad range of products (imines, benzimidazoles, benzothiazoles, quinoxalines and quinolines) and applicability at gram scale reactions are the advantages of the present strategy.
- Adimurthy, Subbarayappa,Badhani, Gaurav,Joshi, Abhisek
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p. 6705 - 6716
(2021/12/31)
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- Cu-Mn Bimetallic Complex Immobilized on Magnetic NPs as an Efficient Catalyst for Domino One-Pot Preparation of Benzimidazole and Biginelli Reactions from Alcohols
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An efficient magnetically recyclable bimetallic catalyst by anchoring copper and manganese complexes on the Fe3O4 NPs was prepared and named as Fe3O4@Cu-Mn. It was founded as a powerful catalyst for the domino one-pot oxidative benzimidazole and Biginelli reactions from benzyl alcohols as a green protocol in the presence of air, under solvent-free and mild conditions. Fe3O4@Cu-Mn NPs were well characterized by FT-IR, XRD, FE-SEM, TEM, VSM, TGA, EDX, DLS, and ICP analyses. The optimum range of parameters such as time, temperature, amount of catalyst, and solvent were investigated for the domino one-pot benzimidazole and Biginelli reactions to find the optimum reaction conditions. The catalyst was compatible with a variety of benzyl alcohols, which provides favorable products with good to high yields for all of derivatives. Hot filtration and Hg poisoning tests from the nanocatalyst revealed the stability, low metal leaching and heterogeneous nature of the catalyst. To prove the synergistic and cooperative effect of the catalytic system, the various homologues of the catalyst were prepared and then applied to a model reaction separately. Finally, the catalyst could be filtered from the reaction mixture simply, and reused for five consecutive cycles with a minimum loss in catalytic activity and performance. Graphic Abstract: A new magnetically recyclable Cu/Mn bimetallic catalyst has been developed for domino one-pot oxidation-condensation of benzimidazole and Biginelli reactions from alcohols. [Figure not available: see fulltext.]
- Nasseri, Mohammad Ali,Rezazadeh, Zinat,Kazemnejadi, Milad,Allahresani, Ali
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p. 1049 - 1067
(2020/09/11)
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- Preparation method of 2-substituted benzimidazole compound
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The invention discloses a preparation method of a 2-substituted benzimidazole compound, and belongs to the field of synthesis of benzimidazole compounds. The 2-substituted benzimidazole compound is synthesized in an organic solvent by taking an o-nitroaniline compound, aromatic aldehyde, o-dinitrobenzene and aromatic aldehyde as raw materials and taking Co particles wrapped by a nitrogen-doped carbon material as a catalyst. According to the method, the 2-substituted benzimidazole compound can be prepared at room temperature, the reaction conditions are mild, the yield is as high as 95%, the selectivity is as high as 99%, and the method is economical, environmentally friendly and wide in substrate applicability. The used catalyst is easy to prepare, low in cost and good in reusability, canbe separated by utilizing magnetism, and is convenient to recover, so that the method has a relatively strong industrial application prospect.
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Paragraph 0035-0078
(2021/02/20)
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- Visible-Light Photoredox Catalyzed Double C-H Functionalization: Radical Cascade Cyclization of Ethers with Benzimidazole-Based Cyanamides
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A visible-light photoredox catalyzed radical cascade cyclization of simple ethers with cyanamides is developed at room temperature. This strategy involves sequential inert Csp3-H/Csp2-H functionalizations through intermolecular addition reaction of oxyalkyl radicals to N-cyano groups followed by radical cyclization of iminyl radicals in situ generated with C-2 aryl rings. This method allows for efficient synthesis of tetracyclic benzo[4,5]imidazo[1,2-c]quinazolines. Importantly, this is the first example of an intermolecular-intramolecular radical cascade cyclization reaction of cyanamides.
- Jiang, Si,Tian, Xiao-Jing,Feng, Shu-Yao,Li, Jiang-Sheng,Li, Zhi-Wei,Lu, Cui-Hong,Li, Chao-Jun,Liu, Wei-Dong
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supporting information
p. 692 - 696
(2021/02/01)
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- Water extract of onion catalyst: An economical green route for the synthesis of 2-substituted and 1,2-disubstituted benzimidazole derivatives with high selectivity
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An efficient, environmental friendly and substrate controlled method of synthesis of 2-substituted benzimidazole derivatives 3 and 1,2-disubstituted benzimidazole derivatives 4 with high selectivity has been achieved from the reaction of o-phenylenediamine 1 and aldehydes 2 in the presence of water extract of onion and selecting suitable reaction medium. This method is widely applicable for variety of aldehydes such as aromatic/aliphatic/heterocyclic aldehydes and 1,2-diamines to afford 2-substituted benzimidazole derivatives 3 and 1,2-disubstituted benzimidazole derivatives 4 in good to excellent yields (up to 96%). The developed method of water extract of onion catalysis produced 2-substituted benzimidazoles 3 from aromatic aldehydes having electron-withdrawing groups, whereas aromatic aldehydes bearing electron donating groups selectively furnished 1,2-disubstituted benzimidazole 4 derivatives. The process described here has several advantages of cheap, low energy consumption, commercially available starting materials, operational simplicity and nontoxic catalyst. The use of water extract of onion makes this present methodology green and giving a useful contribution to the existing methods available for the preparation of benzimidazole derivatives. In addition, Hammett correlation of substituent constant (σ) vs percentage (%) yield has been established.
- Kaliyan, Prabakaran,Selvaraj, Loganathan,Muthu, Seenivasa Perumal
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supporting information
p. 340 - 349
(2020/12/01)
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- Ruthenium(II)-catalyzed synthesis of 2-arylbenzimidazole and 2-arylbenzothiazole in water
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Benzimidazoles/benzothiazoles are heterocyclic compounds which contain a five membered heteroatom and a benzene ring. They constitute a crucial structural unit of numerous bioactive compounds and natural products. Since the compounds containing benzimidaz
- Singh, Keisham S.,Joy, Francis,Devi, Prabha
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p. 181 - 190
(2020/11/26)
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- Tandem Photocatalysis Protocol for Hydrogen Generation/Olefin Hydrogenation Using Pd-g-C3N4-Imine/TiO2Nanoparticles
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An unprecedented visible-light-driven photocatalytic system consisting of Pd nanoparticles stabilized on g-C3N4-imine-functionalized TiO2 nanoparticles was discovered for photoassisted hydrogen generation followed by olefin hydrogenation under mild conditions. The structural integrity of the as-synthesized photocatalyst was corroborated by Fourier transform infrared spectroscopy, X-ray powder diffraction, energy-dispersive X-ray spectroscopy, inductively coupled plasma atomic emission spectroscopy, X-ray photoelectron spectroscopy, ultraviolet-diffuse reflectance spectroscopy, Brunauer-Emmett-Teller measurements, and thermogravimetric analysis (TGA). Transmission electron microscopy and high-resolution scanning electron microscopy revealed the nanoscopic nature of the catalyst. The photocatalyst promoted several different transformations in a one-pot reaction sequence: hydrogen evolution through photocatalytic acceptorless formation of benzimidazoles as important therapeutic agents followed by visible-light-driven photocatalytic reduction of olefins with a high hydrogen utilization efficiency of up to 92% under mild conditions. A significant volume of H2 was produced under blue light-emitting diode (LED) irradiation during the selective formation of benzimidazole, while the selectivity reduced significantly under a Xe lamp or in the dark. The in situ-generated H2 could be activated by the as-prepared Pd-C3N4-imine/TiO2 photocatalyst to effectively hydrogenate olefins under mild conditions at appropriate time exposed to blue LED irradiation. The light-dependent photocatalytic performance of the title catalyst was assessed using action spectra by calculating the apparent quantum efficiency (AQE), which exhibited the maximum AQEs at 410 and 550 nm, at which the highest performance for styrene hydrogenation was obtained. The improved photoredox activity of the title nanohybrid could be caused by the synergistic effects of the heterojunction of carbon nitride-Pd on TiO2 nanoparticles evidenced by photoluminescence spectra and catalytic reactions. The catalyst proved to be air-stable, robust, recyclable, and very active in the absence of any undesirable additives and reducing agents. Thus, this work presents a new protocol for improving the photocatalytic properties of semiconducting materials for various photocatalytic applications under environmentally friendly conditions.
- Jafarpour, Maasoumeh,Feizpour, Fahimeh,Rezaeifard, Abdolreza,Pourmorteza, Narges,Breit, Bernhard
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supporting information
p. 9484 - 9495
(2021/07/19)
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- s-Tetrazine-functionalized hyper-crosslinked polymers for efficient photocatalytic synthesis of benzimidazoles
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Developing green-safe, efficient and recyclable catalysts is crucial for the chemical industry. So far, organic photocatalysis has been proved to be an environmentally friendly and energy-efficient synthetic technology compared with traditional metal catalysis. As a versatile catalytic platform, hyper-crosslinked polymers (HCPs) with large surface area and high stability are easily prepared. In this report, we successfully constructed two porous HCP photocatalysts (TZ-HCPs) featurings-tetrazine units and surface areas larger than 700 m2g?1through Friedel-Crafts alkylation reactions. The rational energy-band structures and coexisting micro- and mesopores endow TZ-HCPs with excellent activities to realize the green synthesis of benzimidazoles (28 examples, up to 99% yield, 0.5-4.0 h) in ethanol. Furthermore, at least 21 iterative catalytic runs mediated by TZ-HCP1D were performed efficiently, with 96-99% yield. This study of TZ-HCPs sheds light on the wide-ranging prospects of application of HCPs as metal-free and green photocatalysts for the preparation of fine chemicals.
- An, Wan-Kai,Zheng, Shi-Jia,Zhang, Hui-Xing,Shang, Tian-Tian,Wang, He-Rui,Xu, Xiao-Jing,Jin, Qiu,Qin, Yuchen,Ren, Yunlai,Jiang, Song,Xu, Cui-Lian,Hou, Mao-Song,Pan, Zhenliang
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supporting information
p. 1292 - 1299
(2021/02/26)
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- Application of sulfonic acid fabricated cobalt ferrite nanoparticles as effective magnetic nanocatalyst for green and facile synthesis of benzimidazoles
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This work represents the design and synthesis of efficient sulfonated cobalt ferrite solid acid catalyst. The synthesized solid acid green catalyst was characterized using various techniques viz. FT-IR, powder XRD, SEM, TEM and VSM. The obtained catalyst was used to synthesize biologically significant 2-substituted benzimidazole derivatives by condensation between o-phenylenediamine with various aromatic, aliphatic and heterocyclic aldehydes. High yield (up to 98 %), short reaction time (10?25 min), mild reaction condition, wide functional group tolerance, easy work-up procedure and excellent values of green chemistry metrices such as lower E factor (0.126), high RME value (88.83 %), carbon efficiency (100 %) and high atom economy (AE) value (90.65 %), are some salient features of the present catalytic system. Moreover, the catalyst recovery by simply using an external magnet and catalyst reusability up to 7 times without any significant loss in catalytic efficiency are some additional remarkable features of the current protocol.
- Yadav, Priyanka,Kakati, Praachi,Singh, Preeti,Awasthi, Satish K.
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- Al2O3/CuI/PANI nanocomposite catalyzed green synthesis of biologically active 2-substituted benzimidazole derivatives
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This work is generally focused on the synthesis of an efficient, reusable and novel heterogeneous Al2O3/CuI/PANI nanocatalyst, which has been well synthesized by a simple self-assembly approach where aniline is oxidized into PANI and
- Chandra, Ramesh,Hooda, Sunita,Kohli, Sahil,Rathee, Garima
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p. 7750 - 7758
(2021/06/16)
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- Benzotrithiophene and triphenylamine based covalent organic frameworks as heterogeneous photocatalysts for benzimidazole synthesis
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Metal-free covalent organic frameworks (COFs) as visible-light active and recyclable photocatalysts afford an eco-friendly and sustainable option to classical photosensitizers, which usually require noble metals (iridium, ruthenium, rhodium, etc.) to produce photocatalytic activity. Most classical small molecule photosensitizers have poor recyclability with certain limitations. As a result, it is of great significance to develop a metal-free and easily recyclable COF photocatalyst. In this study, we designed and synthesized a new type of COF photocatalyst (BTT-TPA-COF) in which benzotrithiophene and triphenylamine units are alternately connected. It has high specific surface area, permanent porosity and good stability. In addition, this design strategy can effectively adjust the band gap, energy level and photoelectric performance of BTT-TPA-COF. As a metal-free photocatalyst, BTT-TPA-COF exhibits high-efficiency photocatalytic activity, excellent substrate tolerance and excellent recyclability for the synthesis of 2-arylbenzimidazole compounds. This research not only puts forward a design strategy for high-efficiency photocatalysts, but also broadens the application range of COF materials in photocatalytic organic reactions.
- Chen, Ying,Huo, Jianqiang,Luo, Bingcai,Zhang, Yubao
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- Bandgap engineering in benzotrithiophene-based conjugated microporous polymers: a strategy for screening metal-free heterogeneous photocatalysts
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Metal-free conjugated microporous polymers (CMPs) as visible-light active and recyclable photocatalysts offer a green and sustainable alternative to classical metal-based photosensitizers. However, the strategy for screening CMP-based heterogeneous photocatalysts has not been interpreted up to now. Herein, we present a general strategy for obtaining excellent solid photocatalysts, which is to implement bandgap engineering in the same series of materials. As a proof of concept, three conjugated porous materials containing benzo[1,2-b:3,4-b′:5,6-b′′]trithiophene building blocks (BTT-CMP1, BTT-CMP2 and BTT-CMP3) were successfully constructed. They possess permanent porosity with a large specific surface area and excellent stability. By changing the linker between benzotrithiophene units, the bandgaps, energy levels and photoelectric performances including the absorption, transient photocurrent responses and photocatalytic performances of BTT-CMPs could be handily modulated. Indeed, BTT-CMP2 displayed the best catalytic activity for visible-light-induced synthesis of benzimidazoles among the three CMP materials, even higher than that of small molecule photocatalysts. As a metal-free photocatalyst, interestingly, the screened BTT-CMP2 also showed extensive substrate applicability and outstanding recyclability. Additionally, we have the opinion that this strategy will prove to be a guiding principle for screening superior CMP-based photocatalysts and broaden their application fields.
- Han, Songjie,Li, Ziping,Ma, Si,Zhi, Yongfeng,Xia, Hong,Chen, Xiong,Liu, Xiaoming
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supporting information
p. 3333 - 3340
(2021/02/26)
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- Nickel-Catalyzed Dehydrogenation of N-Heterocycles Using Molecular Oxygen
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Herein, an efficient and selective nickel-catalyzed dehydrogenation of five- and six-membered N-heterocycles is presented. The transformation occurs in the presence of alkyl, alkoxy, chloro, free hydroxyl and primary amine, internal and terminal olefin, trifluoromethyl, and ester functional groups. Synthesis of an important ligand and the antimalarial drug quinine is demonstrated. Mechanistic studies revealed that the cyclic imine serves as the key intermediate for this stepwise transformation.
- Banerjee, Debasis,Bera, Atanu,Bera, Sourajit
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supporting information
(2020/09/02)
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- An Efficient Greener Approach for N-acylation of Amines in Water Using Benzotriazole Chemistry
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A straightforward, mild and cost-efficient synthesis of various arylamides in water was accomplished using versatile benzotriazole chemistry. Acylation of various amines was achieved in water at room temperature as well as under microwave irradiation. The developed protocol unfolds the synthesis of amino acid aryl amides, drug conjugates and benzimidazoles. The environmentally friendly synthesis, short reaction time, simple workup, high yields, mild conditions and free of racemization are the key advantages of this protocol.
- Ibrahim, Tarek S.,Seliem, Israa A.,Panda, Siva S.,Al-Mahmoudy, Amany M.M.,Abdel-Samii, Zakaria K.M.,Alhakamy, Nabil A.,Asfour, Hani Z.,Elagawany, Mohamed
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- The Direct Rh(III)-Catalyzed C-H Amidation of Aniline Derivatives Using a Pyrimidine Directing Group: The Selective Solvent Controlled Synthesis of 1,2-Diaminobenzenes and Benzimidazoles
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The regioselective Rh(III)-catalyzed C-H amidation of aniline derivatives with dioxazolones as an amidating reagent with a pyrimidine as a directing group leading to the production of 1,2-diaminobenzene derivatives or benzimidazole derivatives is describe
- Chatani, Naoto,Khake, Shrikant M.
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p. 3655 - 3660
(2020/05/22)
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- tert-Butyl nitrite catalyzed synthesis of benzimidazoles from o-phenylenediamine and aldehydes at room temperature
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A simple and efficient method is demonstrated for the synthesis of benzimidazoles via cyclocondensation of o-phenylenediamine with aldehydes in the presence of catalytic amount of tert-butyl nitrite. All the reactions were carried out at room temperature while the desired products were obtained in good to excellent yields.
- Azeez, Sadaf,Chaudhary, Priyanka,Kandasamy, Jeyakumar,Sabiah, Shahulhameed,Sureshbabu, Popuri
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- Transforming Oxadiazolines through Nitrene Intermediates by Energy Transfer Catalysis: Access to Sulfoximines and Benzimidazoles
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Subtle differences in reaction conditions facilitated unprecedented photocatalytic reactions of oxadiazolines by energy transfer catalysis. A set of compounds, sulfoximines and benzimidazoles, were ingeniously prepared from oxadiazolines via nitrene intermediates by photocatalytic N-O/C-N bond cleavages. The synthesis of sulfoximines was realized through intermolecular N-S bond formation between nitrene intermediates and sulfoxides, whereas benzimidazoles were obtained via intramolecular aromatic substitution of the nitrene to the tethered aryl substituent.
- Park, Do Dam,Min, Kwan Hong,Kang, Jihee,Hwang, Ho Seong,Soni, Vineet Kumar,Cho, Cheon-Gyu,Cho, Eun Jin
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supporting information
p. 1130 - 1134
(2020/02/15)
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- Thiophene-embedded conjugated microporous polymers for photocatalysis
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Various photoactive building blocks can be incorporated into porous organic polymers (POPs). The intrinsic properties, such as various synthetic methods, outstanding inherent porosity, easy tunability, rigid conjugated skeletons and high stability, endow the polymeric organic networks with wonderful potential to act as heterogeneous photocatalytic platforms. However, exploitation of efficient synthetic strategies for metal-free and nontoxic heterogenous photocatalysts, and further insights into the photocatalytic process in organic transformations are still necessary. In this context, we report the concise synthesis of two polymeric frameworks (BTP-CMP and TBTP-CMP) incorporated into bithiophene and thiophthene units via a "bottom-up"strategy. BTP-CMP and TBTP-CMP were employed as heterogeneous photocatalysts in the synthesis of benzimidazoles, and exhibited excellent catalytic activity (up to 98% yield, at least 15 iterative runs). Therefore, the thiophene-embedded networks can serve as stable efficient and recyclable heterogeneous photocatalysts. Additionally, based on the catalytic results of control experiments and the energy band structures of the materials and intermediates, a possible photocatalytic reaction mechanism has been proposed.
- An, Wan-Kai,Cao, Zhan-Qi,Ding, San-Yuan,Du, Ya-Nan,Jiang, Song,Li, Zhi-Jun,Liu, Xiaobiao,Pan, Zhenliang,Qin, Yuchen,Song, Meirong,Wei, Pi-Feng,Zheng, Shi-Jia
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p. 5171 - 5180
(2020/09/07)
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- Ultrafine Pt nanoparticles supported on a dendrimer containing thiol groups: An efficient catalyst for the synthesis of benzimidazoles and benzothiazoles from benzyl alcohol derivatives in water
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A novel and unique platform was prepared based on a dendrimer containing thiol groups supported on nanosilica (nSTDP), and ultrafine platinum nanoparticles were synthesized and immobilized on the thiol decorated branches of nSTPD. The new catalyst, (Ptnp?nSTDP), was characterized by different techniques such as FE-SEM, TEM, ICP, XPS and DR UV-vis. This heterogeneous catalyst presented an outstanding performance for the synthesis of benzimidazole and benzothiazole derivatives through a reaction between benzyl alcohol derivatives and 2-aminothiophenol or 1,2-phenylenediamine. No requirement for the pre-reduction of catalysts and using water as a green solvent make it an individual catalyst for these reactions. Furthermore, the catalyst can be easily recovered and reused five consecutive times in the production of benzimidazoles and benzothiazoles without significant leaching of Pt and loss of its activity which illustrated the chemical stability of the catalyst during the reaction.
- Bahadori, Mehrnaz,Landarani-Isfahani, Amir,Mirkhani, Valiollah,Moghadam, Majid,Mohammadpoor-Baltork, Iraj,Nori, Zahra Zamani,Tangestaninejad, Shahram
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p. 33137 - 33147
(2020/10/02)
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- Method for synthesizing benzimidazole compound through copper catalysis
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The invention relates to a method for synthesizing a benzimidazole compound by copper catalysis. The method comprises the following steps: dissolving o-phenylene diamine, benzyl alcohol or substitutedbenzyl alcohol in an organic solvent, adding a copper catalyst, carrying out reactions at a room temperature for 3-6 hours, and separating and purifying the reaction product to obtain the benzimidazole compound. Compared with the prior art, the method has the advantages of simple and green synthesis process, excellent selectivity, high yield and wide substrate range, and has great application potential in drug synthesis, natural product synthesis and the like.
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Paragraph 0032-0034
(2020/05/05)
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- Selective photocatalytic oxidation of aromatic alcohols to aldehydes with air by magnetic WO3ZnO/Fe3O4.: In situ photochemical synthesis of 2-substituted benzimidazoles
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Recently, visible light-driven organic photochemical synthesis has been a pioneering field of interest from academic and industrial associations due to its unique features of green and sustainable chemistry. Herein, WO3ZnO/Fe3O4 was synthesized, characterized, and used as an efficient magnetic photocatalyst in the preparation of a range of 2-substituted benzimidazoles via the condensation of benzyl alcohol and o-phenylenediamine in ethanol at room temperature for the first time. The key feature of this work is focused on the in situ photocatalytic oxidation of benzyl alcohols to benzaldehydes under atmospheric air and in the absence of any further oxidant. This new heterogeneous nanophotocatalyst was characterized via XRD, FT-IR, VSM and SEM. Short reaction time, cost-effectiveness, broad substrate scope, easy work-up by an external magnet, and excellent product yield are the major advantages of the present methodology. A number of effective experimental parameters were also fully investigated to clear broadness and generality of the protocol. This journal is
- Esmaeili, Effat,Li, Bozhi,Maleki, Behrooz,Namaghi, Mina S.,Tayebee, Reza
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p. 40725 - 40738
(2020/11/23)
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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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- Nickel catalysed construction of benzazoles: Via hydrogen atom transfer reactions
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Herein we report a homogeneous, phosphine free, inexpensive nickel catalyst that forms a wide variety of benzazoles from alcohol and diamines by a reaction sequence of alcohol oxidation, imine formation, ring cyclization and dehydrogenative aromatization. A reversible azo/hydrazo couple, that is part of the ligand architecture steers both the alcohol oxidation and dehydrogenation of the annulated amine under fairly mild reaction conditions. Interestingly, both the alcohol oxidation and amine dehydrogenation steps are directly mediated by hydrogen atom transfer (HAT), which is greatly facilitated by the reduced ligand backbone. The kH/kD for the amine dehydrogenation step, measured at 60 °C is 5.9, fully consistent with HAT as the rate determining factor during this step. This is a unique scenario where two consecutive oxidation steps towards benzazole formation undergo HAT, which has been substantiated via kinetic studies, KIE determination and intermediate isolation. This journal is
- Adhikari, Debashis,Bains, Amreen K.,Dey, Dhananjay,Kundu, Abhishek,Yadav, Sudha
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p. 6495 - 6500
(2020/11/13)
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- Solvent-Free N-Alkylation and Dehydrogenative Coupling Catalyzed by a Highly Active Pincer-Nickel Complex
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The synthesis and characterization of a pincer-nickel complex of the type (iPr2NNN)NiCl2(CH3CN) is reported here. We have demonstrated the utility of this pincer-nickel complex (0.02 and 0.002 mol %) for the catalytic N-alkylation of amines using various alcohols. Under solvent-free conditions, while the highest yield (ca. 90%) was obtained for the alkylation of 2-aminopyridine with naphthyl-1-methanol, excellent turnovers (34000 TONs) were observed for the alkylation of 2-aminopyridine with 4-methoxybenzyl alcohol. To demonstrate the synthetic utility of these systems, high-yield reactions (up to 98%) have been probed for representative substrates with a higher loading of the pincer-nickel catalyst (4 mol %). DFT studies indicate that while β-hydride elimination is the RDS for alcohol dehydrogenation, the N-alkylated product can be formed either via hydrogenation with a rate-determining σ-bond metathesis or by alcoholysis that has imine insertion as the RDS. All of the corresponding resting states have been observed by HRMS (ESI) analysis. The labeling experiments are also complementary to DFT studies and show evidence for the involvement of the benzylic C-H bond in the RDS with a kCHH/kCHD value of about 2.5. This method has been applied to accomplish efficient (2000 TONs) dehydrogenative coupling leading to various benzimidazoles.
- Arora, Vinay,Dutta, Moumita,Das, Kanu,Das, Babulal,Srivastava, Hemant Kumar,Srivastava, Hemant Kumar,Kumar, Akshai,Kumar, Akshai
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p. 2162 - 2176
(2020/06/05)
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- New synthesis method of thiabendazole
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The invention relates to a new synthetic route of a drug commonly named as thiabendazole. Thiazole-4-formaldehyde is used as a raw material, and is condensed with hydroxylamine hydrochloride to obtainthiazole-4-formaldoxime, thiazole-4-formaldoxime is subjected to chlorination by using NCS, and then reacts with aniline to obtain N-phenylthiazole-4-methylamine oxime, then N-phenylthiazole-4-methylamine oxime reacts with p-trifluoromethyl benzoyl chloride to obtain an amidoxime ester, and finally a visible-light-catalyzed free radical reaction is adopted for cyclization to obtain thiazole. According to the method, the visible-light-catalyzed free radical reaction is used to the synthesis of thiabendazole for the first time, the reaction conditions of a high temperature and a strong acid inthe traditional synthesis method are avoided, and thereby the reaction is greener and milder. The method has a broad spectrum, and can also be used for synthesis of imidazole compounds Ia-Ial.
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Paragraph 0026; 0035; 0036; 0037; 0038; 0166; 0167
(2020/02/20)
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- 2-ARYLBENZIMIDAZOLES AS PPARGC1A ACTIVATORS FOR TREATING NEURODEGENERATIVE DISEASES
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A genus of compounds encompassed by formula (III) and their use is disclosed: Formula (III). The compounds activate Ppargc1a and, as a consequence, are useful for treating a variety of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Alzheimer's disease, Parkinson's disease, Huntington's disease, frontotemporal degeneration, dementia with Lewy bodies, motor neuron diseases, and a demyelinating disease.
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Paragraph 85; 90
(2020/03/02)
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- Preparation and Characterization of New Heterogeneous Catalyst Polymer-Supported Reagent and its Application in the Green Synthesis of 2-Substituted Benzimidazoles
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A polymer-supported reagent (PSR) was synthesized by exploiting the propensity of Merrifield resin to undergo quaternization with 1-N-methylimidazole followed by anion metathesis reaction. The characterization of PSR was also made by various techniques in
- Joshi-Kulkarni, Kanchan S.,Ajalkar, Babasaheb D.,Kurane, Rajanikant M.,Jadhav, Jagnnath S.
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p. 459 - 464
(2021/02/02)
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- Solid Phase Synthesis of Biologically active Benzimidazole Derivatives Catalysed by CH3S03H-Si02 under Solvent free Condition
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A simple an expeditious method was established for the synthesis of 2-Substituted-1H-Benzimidazole derivatives at 90°C using o-phenylenediamine and different aldehydes. It has been found that a mixture of Methanesulphonic acid-Si02to be an effective catal
- Datta, Arup,Roy, Sanjay
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p. 537 - 543
(2020/07/23)
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- MWCNTs-ZrO2 as a reusable heterogeneous catalyst for the synthesis of N-heterocyclic scaffolds under green reaction medium
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A simple, efficient, and facile heterogeneous multi-walled carbon nanotubes-zirconia nanocomposite (MWCNTs-ZrO2) has been synthesized using natural feedstock coconut juice (água-de-coco do Ceará). The synthesized catalyst was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy analysis. The heterogeneous nanocomposite has been used for one-pot synthesis of various N-heterocyclic compounds like pyrazoles, 1,2-disubstituted benzimidazoles, 2-arylbenzazoles, and 2,3-dihydroquinazolin-4(1H)-ones under green reaction medium at room temperature. This novel method has several advantages, such as short reaction time, simple work-up, excellent yield, and green reaction conditions. The catalyst was recycled up to four times without significant loss in catalytic activity.
- Halder, Bipasa,Banerjee, Flora,Nag, Ahindra
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- Development of homogeneous polyamine organocatalyst for the synthesis of 2-aryl-substituted benzimidazole and benzoxazole derivatives
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A new polyamine was prepared by the ring opening polymerization of epichlorohydrin and properly characterized. The catalytic property of the prepared polymer was assessed by synthesizing 2-aryl-substituted benzimidazole and benzoxazole derivatives by the conjugation of o-phenylenediamine/o-aminophenol with various aromatic aldehydes in the presence of atmospheric oxygen. Significant attributes of the present synthesis include short reaction time, good to excellent yield, high purity, easy reusability, and room temperature reaction. The reaction was carried out in the absence of any metal catalyst and other cooxidants.
- Kottayil, Hiba,Machingal, Shaibuna,Parackal B., Sherly mole,Alungal M., Shebitha,Theresa, Letcy V.,Govindan, Avudaiappan,Krishnapillai, Sreekumar
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p. 3310 - 3317
(2020/07/17)
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- "Metal-Free" Nanoassemblies of AIEE-ICT-Active Pyrazine Derivative: Efficient Photoredox System for the Synthesis of Benzimidazoles
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Supramolecular nanoassemblies of an AIEE-ICT-active pyrazine derivative (TETPY) having strong absorption in the visible region and excellent transportability have been utilized as an efficient photoredox catalytic system for the synthesis of a variety of benzimidazoles having electron-withdrawing/electron-releasing/aliphatic groups under "metal-free"conditions. The reaction protocol involves the successful harvesting of visible light by TETPY assemblies to catalyze the coupling of o-phenylenediamine/substituted diamines and substituted aromatic/heterocyclic/aliphatic aldehydes under aerial conditions using mixed aqueous media as the reaction solvent. TETPY assemblies could activate aerial oxygen to generate superoxide for completing the vital proton abstraction step without the need for any external metal/base/oxidant. Moreover, all the products are purified by recrystallization from organic solvents. The TETPY assemblies also exhibited high efficiency in catalyzing the synthesis of 2-substituted benzothiazoles and quinazolines in excellent yields.
- Dadwal, Shruti,Kumar, Manoj,Bhalla, Vandana
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p. 13906 - 13919
(2020/11/20)
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- Three-Way Chemoselectivity Switching through Coupled Equilibria
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Controlling the chemoselectivity of reactions operating on complex mixtures, including those found in biological and petrochemical feedstocks or in the primordial soup from which life emerged, is generally challenging. The selectivity of imine oxidation c
- Puangsamlee, Thamon,Miljani?, Ognjen ?.
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supporting information
p. 5900 - 5904
(2020/08/05)
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- Formation of Amidinyl Radicals via Visible-Light-Promoted Reduction of N-Phenyl Amidoxime Esters and Application to the Synthesis of 2-Substituted Benzimidazoles
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We have developed a new method for the synthesis of 2-substituted benzimidazoles via amidinyl radicals generated by visible-light-promoted reduction of N-phenyl amidoxime esters in the presence of an iridium photocatalyst. This is the first report of the use of N-phenyl amidoxime esters as amidinyl radical precursors, and the first use of substituted benzene rings as amidinyl radical acceptors. This method widens the application range of substrates and overcomes the shortcomings of the traditional methods for the synthesis of 2-substituted benzimidazoles, which requires harsh reaction conditions, involves difficult-to-prepare substituted o-phenylenediamine substrates, and produces acidic waste.
- Li, Gang,He, Ru,Liu, Qiang,Wang, Ziwen,Liu, Yuxiu,Wang, Qingmin
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p. 8646 - 8660
(2019/07/08)
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