- Benzimidazoles and benzothiazoles from styrenes and N-vinylimidazole via palladium catalysed oxidative C[dbnd]C and C[sbnd]N bond cleavage
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Herein we report a first, palladium catalyzed, one-pot methodology for the synthesis of pharmacologically important benzimidazoles and benzothiazoles from readily available terminal aromatic olefins. The process involves sequential C[dbnd]C/C[sbnd]N bond cleavage followed by C[sbnd]N/C[sbnd]S bond formation.
- Shaikh, Altab,Ravi, Owk,Pushpa Ragini,Sadhana, Nimma,Reddy Bathula, Surendar
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- Diphosphorus tetraiodide (P2I4): An efficient catalyst for synthesis of 2-Aryl-1,3-benzazoles via cyclocondensation of o-Amino/Mercaptan/Hydroxy anilines with aryl acids
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An efficient and versatile approach for the synthesis of 2-substituted 1,3-benzazoles has been developed via diphosphorus tetraiodide (P2I4) catalyzed condensation reaction of ortho-substituted anilines (–NH2, –SH and –OH) with various aromatic acids to give benzimidazoles, benzothiazoles and benzoxazoles in excellent yields. Additionally, the synthetic approach reported herein has advantages such as mild reaction conditions, broad substrate scopes as well as simple one-pot operation, common for all the three 1,3-benzazoles, which makes this strategy highly attractive.
- Bhagat, Saket B.,Sutar, Yogesh B.,Manohar, Yogesh,Telvekar, Vikas N.
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p. 376 - 380
(2018/01/11)
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- Inexpensive weight-reducing aid (L-carnitine) as an efficient catalyst for synthesis of benzimidazoles
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Aim and Objective: The benzimidazole derivatives have been obtained via weight-reducing aid (L-Carnitine) as a cheap catalyst. A wide range of aromatic aldehydes easily undergo condensations with substituted o-phenylendiamine under mild condition to affor
- Zhang, Min,Huang, Guoling,Zhang, Xuefang,Lin, Zhenyuan,Li, Yibiao,Li, Bin,Chen, Lu
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p. 567 - 570
(2019/01/14)
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- Benzimidazoles from Aryl Alkyl Ketones and 2-Amino Anilines by an Iodine Catalyzed Oxidative C(CO)-C(alkyl) Bond Cleavage
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Novel molecular iodine catalyzed cyclization reactions of 2-amino anilines with aryl alkyl ketones under oxidant and metal-free conditions are described. The reaction likely involves sequential C-N bond formation followed by C(CO)-C(alkyl) bond cleavage. Various 2-substituted benzimidazoles are obtained in moderate to good yields in a single step from readily available acetophenones, propiophenones, and phenylacetophenones.
- Ravi, Owk,Shaikh, Altab,Upare, Atul,Singarapu, Kiran Kumar,Bathula, Surendar Reddy
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p. 4422 - 4428
(2017/04/28)
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- Tunable Triazole-Phosphine-Copper Catalysts for the Synthesis of 2-Aryl-1H-benzo[d]imidazoles from Benzyl Alcohols and Diamines by Acceptorless Dehydrogenation and Borrowing Hydrogen Reactions
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Triazole-phosphine-copper complexes (TAP?Cu) have been synthesized and applied as tunable and efficient catalysts for the selective synthesis of fluoro-substituted 2-aryl-1H-benzo[d]imidazole and 1-benzyl-2-aryl-1H-benzo[d]imidazole derivatives from simple alcohols in only one step. TAP?Cu exhibited excellent and tunable catalytic activity for both dehydrogenation and borrowing hydrogen reactions with more than 80 examples being demonstrated for the first time. It was observed that the ligand played a critical role in catalyst activity. Mechanistic studies and deuterium labeling experiments indicated that the reactions proceeded by an initial and reversible alcohol dehydrogenation resulting in a copper hydride intermediate. This was also supported by the direct observation of a diagnostic copper hydride signal by solid-state infrared spectroscopy. The TAP?Cu-H complex showed absorptions at 912 cm?1 that could be assigned to copper?hydride stretches. Furthermore, the direct trapping of an intermediate bisimine was also successfully performed. (Figure presented.).
- Xu, Zhaojun,Wang, Duo-Sheng,Yu, Xiaoli,Yang, Yongchun,Wang, Dawei
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supporting information
p. 3332 - 3340
(2017/10/06)
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- Method for catalytically synthesizing benzimidazole compound in water phase under microwave radiation
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The invention discloses a method for catalytically synthesizing a benzimidazole compound in a water phase under microwave radiation. The method comprises the following steps: adding a catalytic amount of metal chloride, proline lithium and a substituted 2-halogenated aniline substrate, ammonia water, a benzaldehyde derivative, inorganic alkali and water into a reaction container; putting the reaction container into a microwave reaction instrument to react at certain temperature and under certain power; after certain time, decompressing and concentrating; purifying a product through a column chromatography to obtain the benzimidazole compound, wherein the metal chloride in the step is iron chloride, cobalt chloride, nickel chloride or copper chloride, the inorganic alkali in the step is sodium hydroxide, cesium carbonate, sodium carbonate, potassium hydroxide or potassium phosphate, and reaction temperature of the microwave reaction instrument is 20 DEG C to 200 DEG C. The method for preparing the benzimidazole compound, provided by the invention, is environmental-friendly, is simple and convenient to operate, is safe and cheap and is efficient. Compared with the prior art, the method has the advantages of moderate reaction conditions, simplicity in operation, high yield, safety, low cost and environmental friendliness.
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Paragraph 0074
(2017/07/19)
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- Synthesis and in vitro α-chymotrypsin inhibitory activity of 6-chlorobenzimidazole derivatives
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A library of benzimidazole derivatives 1–20 were synthesized, and studied for their α-chymotrypsin (α-CT) inhibitory activity in vitro. Kinetics and molecular docking studies were performed to identify the type of inhibition. Compound 1 was found to be a good inhibitor of α-chymotrypsin enzyme (IC50?=?14.8?±?0.1?μM, Ki?=?16.4?μM), when compared with standard chymostatin (IC50?=?5.7?±?0.13?μM). Compounds 2–8, 15, 17, and 18 showed significant inhibitory activities. All the inhibitors were found to be competitive inhibitors, except compound 17, which was a mixed type inhibitor. The substituents (R) in para and ortho positions of phenyl ring B, apparently played a key role in the inhibitory potential of the series. Compounds 1–20 were also studied for their cytotoxicity profile by using 3T3 mouse fibroblast cells and compounds 3, 5, 6, 8, 12–14, 16, 17, 19, and 20 were found to be cytotoxic. Molecular docking was performed on the most active members of the series in comparison to the standard compound, chymostatin, to identify the most likely binding modes. The compounds reported here can serve as templates for further studies for new inhibitors of α-chymotrypsin and other chymotrypsin-like serine proteases enzymes.[Figure presented]
- Siddiqui, Hina,Farooq, Rabia,Marasini, Bishnu P.,Malik, Rizwana,Syed, Naima,Moin, Syed Tarique,Atta-ur-Rahman,Choudhary, M. Iqbal
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p. 3387 - 3395
(2016/07/20)
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- Copper(I)-Catalyzed regioselective amination of N -aryl imines using TMSN3 and TBHP: A route to substituted benzimidazoles
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A novel and efficient copper-catalyzed amination of N-aryl imines is described. This one-pot, multicomponent reaction, in which imine acts as a directing group by chelating to the metal center, affords a potential route for the transformation of the commercial aryl amines, aldehydes, and azides into valuable benzimidazole structural units with wide substrate scope and diversity. The synthetic and mechanistic aspects are presented.
- Mahesh, Devulapally,Sadhu, Pradeep,Punniyamurthy, Tharmalingam
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p. 1644 - 1650
(2015/02/19)
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- Mesoporous molecular sieve MCM-41 as a novel and efficient catalyst to synthesis of 2-substituted benzimidazoles
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o-Phenylenediamine derivatives readily react with benzoyl chloride derivatives in the presence of MCM-41 as catalyst to yield 2-substituted benzimidazoles in very good yields.
- Heravi, Majid M.,Baghernejad, Bita,Oskooie, Hossein A.,Malakooti
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experimental part
p. 1129 - 1132
(2009/12/25)
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- Synthesis and activities of 5-substituted- -2-(p-substituted phenyl)-1-dialkylaminomethyl benzimidazole derivatives
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Nine 1,2,5-trisubstituted benzimidazole derivatives were prepared and their structure have been elucidated by IR, NMR spectral data and elemental analyses. Analgesic activity of the compounds prepared was investigated in mice by modified KOSTER test. Anti
- Uzunoglu,Tosun,Ozden,Yesilada,Berkem
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p. 619 - 623
(2007/10/03)
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- AN EXPEDIENT ROUTE TO 1H-BENZIMIDAZOLES AND 1H-IMIDAZOPYRIDINES
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1H-Benzimidazoles, 1H-imidazopyridines, and 1H-imidazopyridines can be synthesized readily by reaction of unisolated N-(1-chloroalkyl)pyridinium chlorides with 1,2-benzenediamines, 2,3-pyridinediamine, and 3,4-pyridinediamine, respectively.
- Eynde, Jean-Jacques Vanden,Mayence, Annie,Maquestiau, Andre,Anders, Ernst
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p. 357 - 364
(2007/10/02)
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- A convenient approach to the synthesis of quinoxalines from isoxazolones and 1,2-diaminobenzenes
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2-Aryl-6,7-(un)substituted-quinoxalines (3a-t) and 2-arylbenzimidazoles (4a-t) have been obtained by condensation of 3-aryl-5(4H)-isoxazolones (1a-e) and 4-(un)substituted-1,2-diaminobenzenes (2a-d) under neutral conditions.The mechanism of their formation is illustrated.
- Rao, M Hanmantha,Reddy, A Pandu Ranga,Veeranagaiah, V
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