CuI-Catalyzed Amination of Arylhalides with Guanidines or Amidines: A Facile Synthesis of 1-H-2-Substituted Benzimidazoles

Abstract

CuI/L5 (N,N'-dimethylethylenediamine) proves to be an efficient catalyst system for the amination of arylhalides with guanidines. The same catalyst system is then successfully applied to the one-step synthesis of 1-H-2-amino-benzimidazoles through tandem aminations of 1,2-dihaloarenes in modest yields. This methodology is also applicable for the preparation of 1-H or 1-substutituted 2-aryl- or 2-alkyl-benzimidazoles.

Synthesis of Benzimidazoles via Domino Intra and Intermolecular C‐N Cross‐Coupling Reaction

“…Apart from that, these compounds can also be used for the synthesis of dyes and high‐temperature resistance polymers . Therefore, the construction of benzimidazole derivatives were developed by many researchers via both traditional methods and C‐N cross‐coupling reactions using various transition metals such as Cu, Pd, Co, Zn, and Ru . In this connection, we would like to demonstrate the methodology for the synthesis of benzimidazoles from thiourea in one pot reaction via desulphurization/substitution/domino C‐N cross‐coupling reaction using cobalt source as catalyst under mild reaction conditions.…”

Greener synthesis using hydrogen peroxide in ethyl acetate of alicyclic ring-fused benzimidazoles and anti-tumour benzimidazolequinones

“…3,16,29 There are drawbacks to reported syntheses of alicyclic ring-fused benzimidazoles such as requirements for transition metals, [1][2][3][4][5][6][7][8][9] prior synthesis of cyclization precursors, [10][11][12][13][14][15][16][17] full equivalents of strong base, [17][18][19][20] high molar mass hypervalent iodine reagents, 21 and the formation of mixtures of isomeric products. 22 The most convenient protocol remains the traditional oxidative cyclization of o-cyclic amine substituted anilines, which was first reported in the early 1960s using hydrogen peroxide in the presence of trifluoroacetic acid.…”

Cobalt‐Catalyzed Aerobic Oxidative Cyclization of 2‐Aminoanilines with Isonitriles: Facile Access to 2‐Aminobenzimidazoles

“…More recently, transition metal-catalyzed cyclization reactions have provided attractive alternative routes to access 2-(N-substituted)-aminobenzimidazoles. The copper-catalyzed intramolecular cyclization reactions of thioureas [15] or guanidines (Scheme 1b) [16] and the amination of aryl halides with guanidines (Scheme 1c) [17] eliminate the need for stoichiometric desulfurization agents. Other approaches enable the arylamination of 2-chlorobenzimidazoles either by Pd catalysis [18] or by high temperature [10,19] or high pressure [20] S N Ar protocols (Scheme 1d).…”