- Metal-free selective synthesis of 2-substituted benzimidazoles catalyzed by Br?nsted acidic ionic liquid: Convenient access to one-pot synthesis of N-alkylated 1,2-disubstituted benzimidazoles
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A novel efficient method for the selective synthesis of 2-substituted benzimidazoles is described through condensation reaction of o-phenylenediamines with a wide rang of aliphatic, aromatic and heteroaromatic aldehyde substrates using Br?nsted acidic ionic liquid as a reusable catalyst under metal-free conditions at ambient temperature. Notably, Dodecylimidazolium hydrogen sulfate ([DodecIm][HSO4]) is the most efficient catalyst for good to excellent yields of the corresponding products (up to 98%). Subsequently, this protocol was successfully applied for the preparation of N-alkylated 1,2-disubstituted benzimidazoles in high to excellent yields via sequential one-pot reaction. In addition, catalysts are recycled at least four times without significant loss in activity.
- Senapak, Warapong,Saeeng, Rungnapha,Jaratjaroonphong, Jaray,Promarak, Vinich,Sirion, Uthaiwan
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p. 3543 - 3552
(2019/05/29)
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- Selective Synthesis of 2-Substituted and 1,2-Disubstituted Benzimidazoles Directly from Aromatic Diamines and Alcohols Catalyzed by Molecularly Defined Nonphosphine Manganese(I) Complex
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Herein, we present a selective synthesis of 2-substituted and 1,2-disubstituted benzimidazoles by acceptorless dehydrogenative coupling of aromatic diamine with primary alcohols. The reaction is catalyzed by a phosphine-free tridentate NNS ligand-derived manganese(I) complex.
- Das, Kalicharan,Mondal, Avijit,Srimani, Dipankar
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p. 9553 - 9560
(2018/07/21)
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- One-pot sequential synthesis of 1,2-disubstituted benzimidazoles under metal-free conditions
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An easy and inexpensive method has been developed to access 1,2-disubstituted benzimidazoles following a one-pot sequential coupling/reduction/cyclization process under metal-free neutral conditions.
- Roy, Priyabrata,Pramanik, Animesh
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supporting information
p. 5243 - 5245
(2013/09/02)
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- Copper-mediated synthesis of substituted 2-aryl-N-benzylbenzimidazoles and 2-arylbenzoxazoles via C-H functionalization/C-N/C-O bond formation
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An efficient method for the transformation of N-benzyl bisarylhydrazones and bisaryloxime ethers to functionalized 2-aryl-N-benzylbenzimidazoles and 2-arylbenzoxazoles is described. The protocol involves a copper(II)-mediated cascade C-H functionalization/C-N/C-O bond formation under neutral conditions. Substrates having either electron-donating or -withdrawing substituents undergo the cyclization to afford the target heterocycles at moderate temperature.
- Guru, Murali Mohan,Ali, Md Ashif,Punniyamurthy, Tharmalingam
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experimental part
p. 5295 - 5308
(2011/08/05)
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- Synthesis and antibacterial activity of some novel N-substituted 3-[4-(1-alkyl/acyl/aroyl-1H-benzimidazol-2-yl)phenyl]acrylate derivatives
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Synthesis of a series of novel 3-[4-(1-alkyl/acyl/aroyl-1H-benzimidazol-2- yl)phenyl]acrylate derivatives has been reported. These derivatives are prepared by condensation of o-phenyle-nediamine with 4-bromobenzoic acid to give 2-(4-bromophenyl)-1H-benzimidazole which undergoes Heck reaction with alkyl acrylates to give the above benzimidazole derivatives. Subsequent reactions of these compounds with different types of electrophiles afford a series of the corresponding 1N-substituted alkyl/acyl/-aroyl/sulfonyl derivatives. Furthermore, the antibacterial activities of these compounds have been checked against Staphylococcus aureus and Salmonella typhimurium bacterial strains but the results are found to be disappointing.
- Chaudhari, Raju B.,Vaidya, Sanjay D.,Karale,Pawar,Rindhe, Sahebrao S.
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p. 1208 - 1215
(2011/10/13)
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