25798-65-6Relevant academic research and scientific papers
Copper(II)-Catalyzed Oxidative Cross-Coupling of Anilines, Primary Alkyl Amines, and Sodium Azide Using TBHP: A Route to 2-Substituted Benzimidazoles
Mahesh, Devulapally,Sadhu, Pradeep,Punniyamurthy, Tharmalingam
, p. 3227 - 3234 (2016)
Copper(II)-catalyzed oxidative cross-coupling of anilines, primary alkyl amines, and sodium azide is described in the presence of TBHP at moderate temperature. This one-pot multicomponent protocol involves a domino C-H functionalization, transimination, ortho-selective amination, and a cyclization sequence. The broad substrate scope and functional group compatibility are the significant practical features. The protocol can be extended to the coupling of benzyl alcohols with moderate yields.
Mesoporous silica supported ytterbium as catalyst for synthesis of 1,2-disubstituted benzimidazoles and 2-substituted benzimidazoles
Samanta, Partha Kumar,Banerjee, Rumeli,Richards, Ryan M.,Biswas, Papu
, (2018/08/06)
The benzimidazole ring is an important pharmacophore in contemporary drug discovery. Thus, effort to identifying new compounds containing benzimidazole scaffolds have gained much attention in recent years. In the present study, MCM-41 type mesoporous silica with large pore (l-MSN) supported ytterbium was successfully prepared by wet impregnation method. Among rare earth metal salts, ytterbium triflate has already been widely investigated as a catalyst in organic synthesis but less toxic ytterbium oxide has yet to be explored. Relatively high abundance and low cost of ytterbium with respect to many catalytically active metals (e.g. Pd, Au, Ru, Ir, Pt) offer an opportunity to develop sustainable catalysts for organic conversions. The catalyst has been characterized by various techniques including nitrogen adsorption, FT-IR, TEM, SEM, EDX technique and elemental mapping. The obtained materials exhibit high surface area and a narrow distribution of mesoporosity. The catalytic performance of the Yb@l–MSNs was tested by synthesis of 1,2-disubstituted benzimidazoles and 2-substituted benzimidazoles through the coupling of aldehydes with o-phenylenediamine. The catalyst resulted in excellent yields in short reaction times and the reaction showed tolerance toward both electron-donating and electron-withdrawing functional groups at room temperature. A particularly interesting finding was the solvent selectivity of this reaction; namely, 1,2-disubstituted benzimidazoles generated as major product in water-ethanol, while the 2-substituted benzimidazoles was generated exclusively in non-polar solvents like toluene.
N-chlorosuccinimide/sodium hydroxide-mediated synthesis of benzimidazoles from amidines under mild conditions
Nguyen, Thanh Binh,Ermolenko, Ludmila,Al-Mourabit, Ali
, p. 555 - 563 (2013/08/15)
A convenient room-temperature one-pot procedure for the preparation of benzimidazoles derivatives from N-arylamidines has been developed. The reaction of N-aryl-N'-chloro amidines, generated by the treatment of N-arylamidines with N-chlorosuccinimide, in presence of sodium hydroxide provides benzimidazoles in good to excellent yields. Nitrogen anion generated in situ from succinimide (by-product of the chlorination step using NCS) and hydroxide anion was found to be highly effective as Bronsted base to promote the cyclization into benzimidazole of N-aryl-N'-chloroamidine.
