Facile, eco-friendly, one-pot protocol for the synthesis of indole-imidazole derivatives catalyzed by amino acids

ABSTRACT

An efficient, convenient green approach for the synthesis of indole-based 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles by multicomponent reaction of substituted 2-arylindole-3-carbaldehydes, benzil, substituted anilines, and ammonium acetate using catalytic amino acid (glycine) in ethanol is described. Several amino acids have also been evaluated as organic catalysts for these reactions. The structures of the compounds have been established on the basis of infrared, mass, and ¹H NMR spectral data. The mild reaction conditions, inexpensive/economical reagents, and good yield show the usefulness of this approach.

GRAPHICAL ABSTRACT

KEYWORDS:

• Indole aldehydes
• MCR
• tetraarylimidazoles
• triarylimidazoles

Acknowledgments

The authors are thankful to Higher Education Commission of Pakistan (HEC) for the award of IRSIP fellowship. M.A. Khan puts on record his thanks for the generous support of HEC through their Analytical support provisions. Prof. Gary S. Molander of Department of Chemistry, University of Pennsylvania, USA, was gracious enough to provide necessary laboratory and other analytical facilities to Sadia Naureen and deserves our thanks.