- Cobalt-catalyzed intramolecular C-N and C-O cross-coupling reactions: Synthesis of benzimidazoles and benzoxazoles
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Cobalt(ii)-complex catalyzes efficiently the intramolecular C-N and C-O cross-couplings of Z-N′-(2-halophenyl)-N-phenylamidines and N-(2-bromophenyl)benzamides to afford the corresponding substituted benzimidazoles and benzoxazoles in the presence of K2CO3 at moderate temperature. The protocol is general, air stable and affords the products selectively in moderate to high yield.
- Saha, Prasenjit,Ali, Md Ashif,Ghosh, Pokhraj,Punniyamurthy, Tharmalingam
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experimental part
p. 5692 - 5699
(2011/02/18)
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- Reactivity-controlled regioselectivity: A regiospecific synthesis of 1,2-disubstituted benzimidazoles
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We demonstrate exceptional levels of regioselectivity in the tandem, animation reactions between 1,2-differentiated dihaloarenes and N-substituted amidines, The regiochemical outcome of this Cul-catalyzed reaction is achieved through a combination of N1/N2 chemoselectivity on the amidine and reactivity-controlled X1/X2 chemoselectivity on the 1,2-dihaloarene. This reaction proves to be fairly general for the regiospecific synthesis of 1,2-substituted benzimidazoles.
- Deng, Xiaohu,Mani, Neelakandha S.
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experimental part
p. 680 - 686
(2010/03/04)
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- Ligand-free copper-catalyzed synthesis of substituted benzimidazoles, 2-aminobenzimidazoles, 2-aminobenzothiazoles, and benzoxazoles
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(Chemical Equation Presented) The synthesis of substituted benzimidazoles, 2-aminobenzimidazoles, 2-aminobenzothiazoles, and benzoxazoles is described via intramolecular cyclization of o-bromoaryl derivatives using copper(II) oxide nanoparticles in DMSO under air. The procedure is experimentally simple, general, efficient, and free from addition of external chelating ligands. It is a heterogeneous process and the copper(II) oxide nanoparticles can be recovered and recycled without loss of activity. 2009 American Chemical Society.
- Saha, Prasenjit,Ramana, Tamminana,Purkait, Nibadita,Ali, Md. Ashif,Paul, Rajesh,Punniyamurthy, Tharmalingam
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supporting information; experimental part
p. 8719 - 8725
(2010/02/28)
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- Copper-catalyzed synthesis of benzimidazoles via cascade reactions of o-haloacetanilide derivatives with amidine hydrochlorides
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(Chemical Equation Presented) We have developed an efficient method for the synthesis of benzimidazoles via cascade reactions of o-haloacetoanilide derivatives with amidine hydrochlorides. The protocol uses 10 mol % CuBr as the catalyst, CS2CO
- Yang, Daoshan,Fu, Hua,Hu, Liming,Jiang, Yuyang,Zhao, Yufen
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p. 7841 - 7844
(2008/12/22)
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