- Visible light initiated oxidative coupling of alcohols ando-phenylenediamines to synthesize benzimidazoles over MIL-101(Fe) promoted by plasmonic Au
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The use of visible light to initiate one-pot synergistic/cascade reactions is a green and energy saving strategy. In this manuscript, we report that MIL-101(Fe) can act as a multifunctional catalyst to realize the oxidative condensation betweeno-phenylenediamines and alcohols to synthesize benzimidazoles under visible light. The deposition of plasmonic Au nanoparticles (Au NPs) on MIL-101(Fe) led to significantly improved activity. Both controlled experiments and electron spin resonance (ESR) results revealed that the production of benzimidazoles fromo-phenylenediamines and alcohols involves three sequential steps,i.e., the oxidative dehydrogenation of alcohols to produce aldehydes, the condensation betweeno-phenylenediamines and the aldehydes to produce Schiff bases and their oxidation to form benzimidazoles,viaa superoxide radical (O2˙?)-mediated pathway. The promoting effect of plasmonic Au NPs in this reaction can be ascribed to the effective transfer of the surface plasmon resonance (SPR)-excited hot electrons to the lowest unoccupied molecular orbital (LUMO) of MIL-101(Fe), which led to the generation of more active O2˙?radicals. This study not only provides a green and sustainable way for the synthesis of benzimidazoles, but also highlights the great potential of using rationally designed plasmonic metal NP/MOF nanocomposites as multifunctional catalysts for light initiated one-pot tandem/cascade reactions.
- Hao, Mingming,Li, Zhaohui,Qin, Yuhuan,Xu, Chao
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p. 4161 - 4169
(2021/06/17)
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- Rhodium catalyzed 2-alkyl-benzimidazoles synthesis from benzene-1,2-diamines and tertiary alkylamines as alkylating agents
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Substituted 2-alkyl-benzimidazoles were synthesized from benzene-1,2-diamine and tertiary amines as alkylating agent under polystyrene supported rhodium (Rh@PS) nanoparticles (NPs) catalyzed conditions. The heterogeneous rhodium catalyst was applied first time for the synthesis of 2-alkyl-benzimidazoles. The reaction followed through oxidation of alkylamines, transamination, and oxidative cyclisation with benzene-1,2-diamines for the corresponding products synthesis with good yields. The process is applicable for vast substrate scope, several functional groups are tolerable, and the Rh@PS catalyst is recyclable up to four cycles without significant loss in catalytic activity.
- Yamini,Sharma, Saurabh,Das, Pralay
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- Simple inorganic base promoted C-N and C-C formation: synthesis of benzo[4,5]imidazo[1,2-a]pyridines as functional AIEgens used for detecting picric acid
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Metal-free catalyzed intermolecular tandem Michael addition/cyclization has been developed for the synthesis of benzo[4,5]imidazo[1,2-a]pyridines from α-bromocinnamaldehyde and 2-substituted benzimidazoles. The reaction promoted by a simple inorganic base displays moderate to good yields and good functional group tolerance. The optical properties of some typical products have been investigated. We found that, due to the presence of the benzene ring at the C1-position of benzo[4,5]imidazo[1,2-a]pyridines which restricts intramolecular motion, as a new type of aggregation-induced emission (AIE) luminogen (AIEgen), they show very good solid-state fluorescence with quantum yields up to 88.80%. Importantly, the AIE performance of compound3bcan be useful to detect the nitroaromatic explosive picric acid (PA) with a detection limit and quenching constant of 42.5 nM and 7.27 × 104M?M, respectively.
- Yang, Kai,Luo, Shi-He,Chen, Si-Hong,Cao, Xi-Ying,Zhou, Yong-Jun,Lin, Yan-Lan,Huo, Yan-Ping,Wang, Zhao-Yang
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supporting information
p. 8133 - 8139
(2021/10/04)
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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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- A benzimidazole and synthetic method of derivative thereof (by machine translation)
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The present invention provides a benzimidazole and its derivative synthesis method, the method through the imidazole chloride catalyzed O-phenylenediamine cyclized, realizes the multi-functional chain dibasic and imidazole and 2 - substituted benzimidazole synthesis, method is simple and economic, and the practicability is strong. This invention does not have any other catalyst or additive, synthetic method has good functional group tolerance and excellent yield and purity, reaction time is short, and does not need the harsh reaction conditions, is suitable for industrial production. (by machine translation)
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Paragraph 0045; 0047; 0048; 0050; 0051
(2019/02/10)
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- Supported Rhodium (Rh@PS) Catalyzed Benzimidazoles Synthesis Using Ethanol/Methanol as C2H3/CH Source
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An effective and stable polystyrene supported rhodium (Rh@PS) nano-catalyst has been synthesized by following reduction-deposition approach and applied for the selective benzimidazoles synthesis from 1,2-phenylenediamines and ethanol/methanol as C2H3/CH source. The ethanol/methanol in the presence of trace amounts of aerobic oxygen under Rh@PS catalysed condition, first participated in oxidation of alcohol followed by consecutive condensation, cyclization and hydrogen elimination reactions with 1,2-phenylenediamine gave the desired products in good yields. The Rh@PS catalyst in a single system performed both oxidation and reduction reactions in a selective/specific manner and applied for large substrate scope. Easy recovery, handling, stability, recyclability of the catalyst and less chance of metal contamination with the products are the added advantages of the process. (Figure presented.).
- Sharma, Saurabh,Sharma, Ajay,Yamini,Das, Pralay
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supporting information
p. 67 - 72
(2018/12/05)
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- Benzimidazoles as Metal-Free and Recyclable Hydrides for CO2 Reduction to Formate
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We report a novel metal-free chemical reduction of CO2 by a recyclable benzimidazole-based organo-hydride, whose choice was guided by quantum chemical calculations. Notably, benzimidazole-based hydride donors rival the hydride-donating abilities of noble-metal-based hydrides such as [Ru(tpy)(bpy)H]+ and [Pt(depe)2H]+. Chemical CO2 reduction to the formate anion (HCOO-) was carried out in the absence of biological enzymes, a sacrificial Lewis acid, or a base to activate the substrate or reductant. 13CO2 experiments confirmed the formation of H13COO- by CO2 reduction with the formate product characterized by 1H NMR and 13C NMR spectroscopy and ESI-MS. The highest formate yield of 66% was obtained in the presence of potassium tetrafluoroborate under mild conditions. The likely role of exogenous salt additives in this reaction is to stabilize and shift the equilibrium toward the ionic products. After CO2 reduction, the benzimidazole-based hydride donor was quantitatively oxidized to its aromatic benzimidazolium cation, establishing its recyclability. In addition, we electrochemically reduced the benzimidazolium cation to its organo-hydride form in quantitative yield, demonstrating its potential for electrocatalytic CO2 reduction. These results serve as a proof of concept for the electrocatalytic reduction of CO2 by sustainable, recyclable, and metal-free organo-hydrides.
- Lim, Chern-Hooi,Ilic, Stefan,Alherz, Abdulaziz,Worrell, Brady T.,Bacon, Samuel S.,Hynes, James T.,Glusac, Ksenija D.,Musgrave, Charles B.
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supporting information
p. 272 - 280
(2019/01/04)
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- Oxalic/malonic acids as carbon building blocks for benzazole, quinazoline and quinazolinone synthesis
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An oxidant, base and metal free methodology has been developed for the synthesis of various 2-substituted and non-substituted benzazoles, quinazolines and quinazolinones using oxalic/malonic acids as an in situ carbon source. This methodology is applicable for a wide range of substituted o-phenylenediamine, o-aminothiophenol, o-aminophenol and o-aminobenzamide containing various functional groups and provides good to excellent yields of the corresponding product. Furthermore an easy workup procedure, high yield and easy isolation of products are key features of this methodology. The developed protocol is also applicable for the gram scale synthesis of benzimidazoles.
- Sharma, Saurabh,Bhattacherjee, Dhananjay,Das, Pralay
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supporting information
p. 1337 - 1342
(2018/03/06)
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- Imidazolium chloride-catalyzed synthesis of benzimidazoles and 2-substituted benzimidazoles from o-phenylenediamines and DMF derivatives
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A facile, general, and economical synthesis of diversely functionalized benzimidazoles and 2-substituted benzimidazoles has been realized via the imidazolium chloride-catalyzed cyclization of o-phenylenediamines with DMF derivatives. This protocol shows a broad substrate scope for aliphatic, aromatic, and heteroaromatic amides. A series of benzimidazoles and 2-substituted benzimidazoles have been obtained in moderate to excellent yields.
- Gan, Zongjie,Tian, Qingqiang,Shang, Suqin,Luo, Wen,Dai, Zeshu,Wang, Huajun,Li, Dan,Wang, Xuetong,Yuan, Jianyong
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p. 7450 - 7456
(2018/11/27)
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- Silica–ferric chloride (SiO2–FeCl3) catalyzed selective synthesis of 2-substituted benzimidazole through Csp2Csp3bond cleavage of β-ketoester/amide
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Silica–ferric chloride (SiO2–FeCl3) supported reagent was successfully utilized as recyclable catalyst for the general and highly efficient synthesis of 2-substituted benzimidazole by the condensation of 1,2-diamino benzene and β-ketoester/amide followed by original Csp2Csp3bond cleavage. Evidences in favor of C[sbnd]C (α–β) bond cleavage of β-ketoesters/amides are established.
- Majumdar, Swapan,Chakraborty, Ankita,Bhattacharjee, Subrata,Debnath, Sudipto,Maiti, Dilip K.
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supporting information
p. 4595 - 4598
(2016/09/23)
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- Discovery of the First Potent and Selective Inhibitors of Human dCTP Pyrophosphatase 1
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The dCTPase pyrophosphatase 1 (dCTPase) regulates the intracellular nucleotide pool through hydrolytic degradation of canonical and noncanonical nucleotide triphosphates (dNTPs). dCTPase is highly expressed in multiple carcinomas and is associated with cancer cell stemness. Here we report on the development of the first potent and selective dCTPase inhibitors that enhance the cytotoxic effect of cytidine analogues in leukemia cells. Boronate 30 displays a promising in vitro ADME profile, including plasma and mouse microsomal half-lives, aqueous solubility, cell permeability and CYP inhibition, deeming it a suitable compound for in vivo studies.
- Llona-Minguez, Sabin,H?glund, Andreas,Jacques, Sylvain A.,Johansson, Lars,Calderón-Monta?o, José Manuel,Claesson, Magnus,Loseva, Olga,Valerie, Nicholas C. K.,Lundb?ck, Thomas,Piedrafita, Javier,Maga, Giovanni,Crespan, Emmanuele,Meijer, Laurent,Burgos Morón, Estefanía,Baranczewski, Pawel,Hagbj?rk, Ann-Louise,Svensson, Richard,Wiita, Elisee,Alml?f, Ingrid,Visnes, Torkild,Jeppsson, Fredrik,Sigmundsson, Kristmundur,Jensen, Annika Jenmalm,Artursson, Per,Jemth, Ann-Sofie,Stenmark, P?l,Warpman Berglund, Ulrika,Scobie, Martin,Helleday, Thomas
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p. 1140 - 1148
(2016/02/23)
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- Novel strategy for synthesis of substituted benzimidazo[1,2-a]quinolines
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An efficient method for the synthesis of benzimidazo[1,2-a]quinolines under transition-metal-free conditions has been developed through a cascade reaction involving sequential aromatic nucleophilic substitution and intramolecular Knoevenagel condensation reactions. This method is applicable for the synthesis of a wide range of benzimidazo[1,2-a]quinoline derivatives from readily available 2-fluoroarylaldehyde and benzimidazole substrates.
- Kato, Jun-Ya,Ito, Yutaro,Ijuin, Ryosuke,Aoyama, Hiroshi,Yokomatsu, Tsutomu
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supporting information
p. 3794 - 3797
(2013/08/23)
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- Microwave-assisted synthesis of polysubstituted benzimidazoles by heterogeneous Pd-catalyzed oxidative C-H activation of tertiary amines
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Tertiary amines can be used in place of aldehydes and carboxylic derivatives as partners in the synthesis of benzimidazoles. Dehydrogenative amine activation under heterogeneous catalysis was developed for the direct transformation of tertiary amines into benzimidazoles. Good yields and efficient recovery and recycling of the catalyst are some of the advantages of this new methodology, which shows that a simple alkene is used as the overall oxidative agent. Enhanced reaction rates were observed by using focused microwave heating.
- De Luca, Lidia,Porcheddu, Andrea
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supporting information; experimental part
p. 5791 - 5795
(2011/11/06)
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- Expeditious and efficient synthesis of benzoxazoles, benzothiazoles, benzimidazoles catalyzed by Ga(OTf)3 under solvent-free conditions
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A new and efficient method for the synthesis of benzoxazoles, benzothiazoles, benzimidazoles from reactions of o-substituted aminoaromatics with orthoesters in the presence of catalytic amounts of Ga(OTf)3 under solvent-free conditions is presented. The remarkable features of this new protocol are high conversion, very short reaction times, cleaner reaction profiles under solvent-free conditions, straight forward procedure, and use of relatively non-toxic catalysts.
- Liu, Juyan,Liu, Qian,Xu, Wei,Wang, Weilu
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experimental part
p. 1739 - 1744
(2012/02/14)
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- Lewis acid catalyst free synthesis of benzimidazoles and formamidines in 1,1,1,3,3,3-hexafluoro-2-propanol
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A simple, inexpensive, environmentally friendly and efficient route for the synthesis of benzimidazole and formamidine derivatives by the reaction of O-phenylenediamines or amines with orthoesters using hexafluoroisopropanol as a solvent/catalyst is described.
- Khaksar, Samad,Heydari, Akbar,Tajbakhsh, Mahmood,Vahdat, Seyed Mohammad
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experimental part
p. 1377 - 1381
(2011/02/22)
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- Easy access to triazoles, triazolopyrimidines, benzimidazoles and imidazoles from imidates
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We have described a new and easy synthesis of triazoles, triazolopyrimidines, benzimidazoles and imidazoles variously substituted based on the reaction of imidates with diamine derivatives. The products were obtained in moderate to good yields. A general mechanism for the reactions is proposed.
- Zarguil,Boukhris,El Efrit,Souizi,Essassi
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body text
p. 5883 - 5886
(2009/04/05)
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- A mild, efficient and one-pot synthesis of 2-substituted benzimidazoles by ZrOCl2. 8H2O catalyzed ring closure reaction
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A mild, efficient and one-pot synthesis of an array of 2-substituted benzimidazoles from an appropriate o-phenylenediamine and orthoesters such as orthoformate, orthoacetate and orthovalerate using ZrOCl2-8H 2O, at room temperature and under microwave irradiation is described. Ecofriendly, solvent-free methodology has been employed under microwave condition. Compared with the conventional method, microwave irradiation method has the advantages of excellent yields (81-93%) and shorter reaction time (5-10 min).
- Sanjeeva Reddy,Nagaraj
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experimental part
p. 1154 - 1159
(2009/04/11)
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- A facile one-pot synthesis of benzimidazoles from 2-nitroanilines by reductive cyclization
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A facile one-pot process to prepare benzimidazole derivatives is described. Reductive cyclization of a serial of 2-nitroanilines with orthoesters in the presence of Pd/C in methanol at room temperature, which is promoted by a catalytic amount of acetic acid, affords the corresponding benzimidazole derivatives in high yields.
- Liu, Zheng,Li, Haihong,Zhao, Qingjie,Shen, Jingshan
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scheme or table
p. 1907 - 1911
(2009/04/06)
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- PEG-mediated catalyst-free expeditious synthesis of 2-substituted benzimidazoles and bis-benzimidazoles under solvent-less conditions
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A wide variety of 2-substituted benzimidazoles and bis-benzimidazoles were synthesized in high yields by PEG-mediated catalyst-free synthesis under solvent-less conditions. The products were directly recrystallized from hot methanol. The reaction occurred giving excellent yields with low as well as high molecular weight PEGs.
- Mukhopadhyay, Chhanda,Tapaswi, Pradip Kumar
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experimental part
p. 6237 - 6240
(2009/04/04)
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- ZNCL2 - promoted synthesis of benzimidazoles under microwave irradiation
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Benzimidazoles 3a-f have been prepared in a few seconds from the reaction of ophenylene-diamine 1 and β-ketoesters 2 on the surface of silica gel and ZnCl2 under microwave irradiation in excellent yield. The reaction has also gone very well in MeOH and in the presence of ZnCl2 under reflux condition.
- Rostamizadeh, Shahnaz,Nojavan, Masoomeh,Heshmatpoor
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p. 305 - 310
(2008/03/13)
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- A highly effective sulfamic acid/methanol catalytic system for the synthesis of benzimidazole derivatives at room temperature
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Sulfamic acid/methanol was found to be an efficient catalytic system for the synthesis of benzimidazole compounds through the condensation of o-phenylenediamine with orthoester in high yields at room temperature.
- Zhang, Zhan-Hui,Li, Tong-Shuang,Li, Jian-Jiong
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- Synthesis of 2-substituted benzimidazoles by iodine-mediated condensation of orthoesters with 1,2-phenylenediamines
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(Chemical Equation Presented) Iodine was found to be an efficient catalyst for the synthesis of 2-substituted benzimidazoles by the condensation of orthoesters and 1,2-phenylenediamines in good to excellent yields under mild reaction conditions.
- Zhang, Zhan-Hui,Li, Jian-Jiong,Gao, Yuan-Zhe,Liu, Yu-Heng
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p. 1509 - 1512
(2008/09/18)
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- Formation of the dimethylbenzimidazole ligand of coenzyme B12 under physiological conditions by a facile oxidative cascade
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(Matrix presented) Dimethylbezimidazole, the axial ligand of vitamin B 12, is synthesized from riboflavin by a two-electron oxidation, a retro-aldol condensation, and a second two-electron oxidation. This oxidative cascade readily takes place nonenzymatically under physiological conditions.
- Maggio-Hall, Lori A.,Dorrestein, Pieter C.,Escalante-Semerena, Jorge C.,Begley, Tadhg P.
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p. 2211 - 2213
(2007/10/03)
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- Clay catalysis: Condensation of orthoesters with O-substituted aminoaromatics into heterocycles
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KSF clay catalysed the condensation of orthoesters with o-substituted aminoaromatics into heterocycles in toluene under reflux or without solvent under microwave irradiation.
- Villemin, Didier,Hammadi, Mohamed,Martin, Benoit
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p. 2895 - 2899
(2007/10/03)
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Arylimidazoles are prepared in good yields on solid mineral supports in "dry media" and under microwave irradiation in domestic ovens.
- Bougrin, Khalid,Soufiaoui, Mohamed
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p. 3683 - 3686
(2007/10/02)
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- NITRATION DE BENZIMIDAZOLES SUBSTITUES
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The mononitration of some 2-Alkyl-5(6)chloro-(or methyl-)benzimidazoles was carried out because the chemical literature results were ambiguous.Our work has shown that the nitro group was introduced in 6 (or 5) position.
- Benchidmi, M.,Kihel, A. El,Essassi, E. M.,Knouzi, N.,Toupet, L.,et al.
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p. 605 - 612
(2007/10/02)
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- ACTION DES O-PHENYLENEDIAMINES SUR LA 2,6-DIMETHYL PYR-4-ONE ET LA 1,3-DIACETYLACETONE
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Condensation of o-phenylenediamines with 2,6-dimethylpyr-4-ones gave 2-methyl benzimidazoles and 1-(o-aminophenyl)-2,6-dimethyl pyrid-4-ones.These laters compounds and 2-acetonylidene-4-methyl-1,5-benzodiazepines are obtained when o-phenylenediamines are reacted with 1,3-diacetylacetone.
- Djerrari, B.,Essassi, E. M.,Fifani, J.
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p. 565 - 574
(2007/10/02)
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- ENZYMATIC CYCLIZATION INVOLVING INTRAMOLECULAR MICHAEL ADDITION BY CATALASE: FORMATION OF 2-METHYLBENZIMIDAZOLES
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Catalase-mediated intramolecular cyclization of ethyl β-2-aminoanilinocrotonates gives 2-methylbenzimidazoles in good yields
- Kamal, Ahmed,Hashim, Riaz
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p. 969 - 970
(2007/10/02)
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- NOUVELLE SYNTHESE DES BENZODIAZEPINES-1,5 A PARTIR DE LA γ-PYRONE
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Reaction of o-phenylenediamines 2, 3 with 2-hydroxy-6-methyl-4-pyrone leads to: 2-butoxycarbonylmethylene-4-methyl-1,5-benzodiazepines 4, 5, 4-acetylmethylene-1,5-benzodiazepin-2-ones 6, 7, and benzimidazoles 8, 11.These compounds result from competitive reactions and different ways of cyclization.
- Abbassi, M. El,Essassi, E. M.,Fifani, J.
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p. 1389 - 1392
(2007/10/02)
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- Phthalone derivatives utilizable as pigments
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Phthalones derived from benzimidazole can be represented by one of the following general formulas: STR1 in which A1 and A2 each represents an aliphatic, alicyclic, aromatic or heterocyclic radical, possibly substituted by one or more nonsolubilizing substituents, and each of the benzene nuclei B1 and B2 can bear one or two substituents selected from halogen atoms and the lower alkyl, lower alkoxy, nitro, acylamino and aryl groups or be coupled with another benzene nucleus. These phthalones are valuable pigments for textile printing and for coloring inks, lacquers, paints, varnishes and plastic materials.
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