Room temperature synthesis of benzimidazole derivatives using reusable cobalt hydroxide (II) and cobalt oxide (II) as efficient solid catalysts

s-Tetrazine based molecules were prepared for visible-light-driven organic transformations. The 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) derivative shows visible light absorption and reversible one-electron reduction behavior. In the presence of pytz and aerial oxygen, aldehyde reacts with o-phenylenediamine or o-aminothiophenol under visible light irradiation at ambient temperature to produce corresponding 2-substituted benzimidazoles and benzothiazoles, respectively. Pytz catalyst demonstrates excellent catalytic activity for alkyl, aryl, organo-metallic substituted aldehydes and reducing sugar. The reaction yield is high for both the electron-donating and electron withdrawing substituents in aromatic aldehydes. The use of a metal-free catalyst and visible light energy, along with the mild reaction conditions, makes this reaction an environmentally benign and energy-saving chemical process.

Photocatalysis by 3,6-disubstituted-s-tetrazine: visible-light driven metal-free green synthesis of 2-substituted benzimidazole and benzothiazole.

Remarkable influence of substituent in ionic liquid in control of reaction: simple, efficient and hazardous organic solvent free procedure for the synthesis of 2-aryl benzimidazoles promoted by ionic liquid, [pmim]BF4

A simple and efficient protocol has been developed for the synthesis of biologically relevant 2-substituted benzimidazoles and quinoxalines using magnetically separable manganese ferrite (MnFe2O4) nanopowder for the first time as a reusable heterogeneous catalyst at room temperature under aerobic conditions. MnFe2O4 nanoparticles were prepared by a simple sol–gel method using starch as a bio-polymeric matrix, and characterized by XRD, TEM, EDAX and VSM analyses.

Magnetically separable MnFe2O4 nano-material: an efficient and reusable heterogeneous catalyst for the synthesis of 2-substituted benzimidazoles and the extended synthesis of quinoxalines at room temperature under aerobic conditions

Synthetic approaches to 2-arylbenzimidazoles: A review

Simple and mild procedures for synthesis of benzimidazole derivatives using heterogeneous catalyst systems

TsOH/graphite and N,N-dimethylaniline/graphite were found to be catalyst systems for condensation reaction of o-phenylendiamine with different aldehydes to form benzimidazole derivatives under mild and simple conditions. The graphite was easily recovered by a simple extraction and could be reused without decrease of activity in the presence of fresh TsOH and N,N-dimethylaniline.

Seyed Mohammad Hossein Tabaei

Papers

Simple and mild procedures for synthesis of benzimidazole derivatives using heterogeneous catalyst systems

Simple and Mild Procedures for Synthesis of Benzimidazole Derivatives Using Heterogeneous Catalyst Systems.