title: Facile and efficient one-pot synthesis of benzimidazoles using lanthanum chloride.
abstract: BACKGROUND
  We report the synthesis of benzimidazoles using lanthanum chloride as an efficient catalyst. One-pot synthesis of 2-substituted benzimidazole derivatives from o-phenylenediamine and a variety of aldehydes were developed under mild reaction conditions.
  
  
  RESULTS
  We have examined the effect of different solvents using the same reaction conditions. The yield of the product varied with the nature of the solvents, and better conversion and easy isolation of products were found with acetonitrile. In a similar manner, the reaction with o-phenylenediamine and 3,4,5-trimethoxybenzaldehyde was carried out without any solvents. The observation shows that the reaction was not brought into completion, even after starting for a period of 9 h, and the reaction mixture showed a number of spots in thin-layer chromatography.
  
  
  CONCLUSIONS
  In conclusion, lanthanum chloride has been employed as a novel and efficient catalyst for the synthesis of benzimidazoles in good yields from o-phenylenediamine and a wide variety of aldehydes. All of the reactions were carried out in the presence of lanthanum chloride (10 mol%) in acetonitrile at room temperature.
authors.affiliation: Department of Chemistry, Osmania University College for Women, Koti, Hyderabad 500095, India. ameshteja_2001@yahoo.co.in.
authors.forename: Yekkirala
authors.initials: Y
authors.lastname: Venkateswarlu
authors.forename: Sudhagani Ramesh
authors.initials: SR
authors.lastname: Kumar
authors.forename: Panuganti
authors.initials: P
authors.lastname: Leelavathi
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