1046136-03-1Relevant academic research and scientific papers
Electrophilic cyclization of N-alkynyl-2-(organochalcogen)imidazoles: An alternative access to imidazo[2,1-b]chalcogenazoles
Grimaldi, Tamiris B.,Godoi, Benhur,Roehrs, Juliano A.,Speranca, Adriane,Zeni, Gilson
supporting information, p. 2646 - 2652 (2013/06/05)
We present here a practical synthesis of multifunctional imidazo[2,1-b]chalcogenazoles through electrophilic cyclization of N-alkynyl-2-(organochalcogen)imidazoles. The cyclization reaction proceeded cleanly and smoothly under mild reaction conditions in the presence of air. The methodology was highly regioselective: In a competition between the chalcogen and oxygen atoms, only S-, and Se-heterocycles were obtained. The resulting imidazo[2,1-b]chalcogenazoles proved to be versatile as precursors for the synthesis of more highly functionalized imidazoselenazoles through copper-catalyzed cross-coupling reactions with arene- and alkanethiols, leading to Ullmann-type products in good yields. We present here a practical synthesis of multifunctional imidazo[2,1-b]chalcogenazoles through electrophilic cyclization of N-alkynyl-2-(organochalcogen)imidazoles. The methodology was highly regioselective: In a competition between the chalcogen and oxygen atoms, only S- and Se-heterocycles were obtained. The resulting imidazo[2,1-b] chalcogenazoles proved to be versatile as precursors for the synthesis of more highly functionalized imidazoselenazoles. Copyright
A simple and efficient copper-catalyzed synthesis of N-alkynylimidazoles
Wang, Man-Gang,Wu, Jun,Shang, Zhi-Cai
supporting information; experimental part, p. 589 - 594 (2012/03/27)
A simple and efficient method for the synthesis of N-alkynylheteroarenes from 1,1-dibromo-1-alkenes was developed via a copper-catalyzed cross-coupling reaction. Generally superior yields and functional-group tolerance were obtained with TMEDA as ligand using imidazole and benzimidazole substrates in dioxane. Georg Thieme Verlag Stuttgart · New York.
Three-step one-pot synthesis of imidazo[2,1-b]chalcogenazoles via intramolecular cyclization of N-alkynylimidazoles
Roehrs, Juliano Alex,Pistoia, Renan P.,Back, Davi F.,Zeni, Gilson
supporting information; experimental part, p. 1791 - 1796 (2012/07/31)
Imidazo-chalcogenazoles are easily accessible from the corresponding N-alkynylimidazoles by a three-step, one-pot chalcogenation reaction. The generality of this reaction has been established with various substituted N-alkynylimidazoles as well as elemental chalcogens. By accessing the key intermediate 2-chalcogenolate-N-alkynylimidazole it was also possible to prepare dichalcogenide derivatives. Copyright
Copper-catalyzed coupling of imidazoles and pyrazoles with 1,1-dibromo-1-alkenes: A distinct approach for direct N-alkynylation of heteroarenes
Das, Biswanath,Salvanna,Reddy, Gandolla Chinna,Balasubramanyam, Penagaluri
experimental part, p. 6497 - 6500 (2011/12/15)
The direct N-alkynylation of heteroarenes, imidazoles, and pyrazoles with 1,1-dibromo-1-alkene has been carried out for the first time using [Cu(Phen)PPh3Br] (as a catalyst) and Cs2CO3 in DMSO at 80 °C. The products are formed in good to high yields (66-85%) within 3 h. No side products could be detected.
Copper(II) oxide catalyzed ligand-free coupling reaction of heteroarenes with bromoalkynes
Das, Biswanath,Reddy, Gandolla Chinna,Balasubramanyam, Penagaluri,Salvanna
experimental part, p. 816 - 820 (2011/04/25)
The coupling reaction of imidazoles and pyrazoles with bromoacetylenes has efficiently been carried out under ligand-free conditions in the presence of copper(II) oxide as the catalyst using potassium hydroxide in 1,4-dioxane at 80 C. The method is a simpler access to N-alk-1-ynyl- and/or N-(2-bromovinyl)- substituted heteroarenes. Georg Thieme Verlag Stuttgart New York.
Cu-catalyzed N-alkynylation of imidazoles, benzimidazoles, indazoles, and pyrazoles using PEG as solvent medium
Burley, Glenn A.,Davies, David L.,Griffith, Gerry A.,Lee, Michael,Singh, Kuldip
supporting information; experimental part, p. 980 - 983 (2010/05/18)
(Chemical Equation Presented) A facile and efficient Cu(I)-catalyzed cross-coupling method is reported for the preparation of N-alkynyl or N-bromoalkenyl heteroarenes from bromoalkynes. Generally superior yields and functional group tolerance were obtained with microwave (MW) irradiation using imidazole, benzimidazole, pyrazole, and indazole substrates and poly(ethylene glycol) 400 (PEG400) as an additive. We speculate that PEG400 acts as both a Cu(I)-stabilizing ligand as well as a phase transfer solvent.
Coupling reactions of bromoalkynes with imidazoles mediated by copper salts: Synthesis of novel N-alkynylimidazoles
Laroche, Christophe,Li, Jing,Freyer, Matthew W.,Kerwin, Sean M.
, p. 6462 - 6465 (2008/12/22)
(Chemical Equation Presented) A cross-coupling reaction of imidazoles with bromoalkynes in the presence of a catalytic amount of CuI is reported. This protocol allows an access to novel N-(1-alkynyl)imidazoles in moderate to good yields.
