2-Substituted benzimidazoles have been synthesized in a one-pot reaction from o- phenylenediamine and aldehydes in the presence of boric acid in water at room temperature. The method was proved to be eco-friendly, convenient and the products were isolated with good yields.
[Lewis, Jared C.; Berman, Ashley M.; Bergman, Robert G.; Ellman, Jonathan A. Journal of the American Chemical Society, 2008 , vol. 130, # 8 p. 2493 - 2500]
