Grindstone chemistry: protic ionic liquid-substrate tuned green synthesis of 1,2-disubstituted and 2-substituted benzimidazoles with outstanding selectivity

  • 10.1039/c5ra08183a
  • RSC Adv.
  • p 51012-51018, Volume 5, Issue 63,
  • journal-article
An environmentally benign and highly catalyst-substrate controlled synthesis of 1,2-disubstituted and 2-substituted benzimidazoles with outstanding selectivity has been developed through grinding a mixture ofo -phenylenediamines, suitable aldehydes and an imidazolium trifluoroacetate protic ionic liquid catalyst. The newly developed metal-free catalysis approach produced 1,2-disubstituted benzimidazoles from aromatic aldehydes bearing electron donating group, whereas aromatic aldehydes possessing electron withdrawing groups and aldehydes with 2-alkoxy substitution selectively furnished 2-substituted benzimidazoles and their chiral analogues. Low energy consumption, short reaction time and solvent-free synthesis make this methodology green, providing a useful contribution to the existing procedures available for the synthesis of benzimidazole derivatives.

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Innovative, but better methods known

Summary:

An efficient and environmentally benign method for synthesis of 1,2-disubstituted and 2 substituted benzimidazoles has been described. Although previous methods are available in literature for synthesis of such compounds, the ease of operation, solvent-free...

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