Title:L-Pipecolic Acid-catalyzed Highly Efficient Synthesis of 2,4,5-Trisubstituted
Imidazoles and N-cycloalkyl-2,4,5-trisubstituted Imidazoles
Volume: 11
Issue: 3
Author(s): Anila Mishra, Zeeshan Fatima*, Akash Ved, Sajal Srivastava and Ashok K Singh
Affiliation:
- Amity Institute of Pharmacy, Amity University, Sector-125, Lucknow, Uttar Pradesh, Noida, 201313, India
Keywords:
One-pot multicomponent reactions (MCRs), L-Pipecolic acid, 2, 4, 5-trisubstituted imidazoles, N-cycloalkylated-2, 5- trisubstituted imidazoles, bifunctional catalyst, non-chromatographic method.
Abstract:
Aims: We aimed to conduct an L-Pipecolic acid-catalyzed synthesis of 2,4,5-trisubstituted
imidazoles and N-cycloalkyl-2,4,5- trisubstituted imidazoles to develop a novel synthetic
route followed by the synthesis of novel series of compounds.
Background: A rapid, highly efficient, and greener approach for the synthesis of a series of 2,4,5-
trisubstituted imidazoles and N-cycloalkyl-2,4,5- trisubstituted imidazoles were developed via onepot
multicomponent reaction (MCRs).
Objective: The objective of the current study was to discover a new and highly efficient organocatalyzed
synthetic route for the synthesis of 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted
imidazoles followed by the synthesis of novel series of compounds.
Method: L-Pipecolic acid was used as a bifunctional catalyst in one-pot multicomponent reaction
(MCRs) for the cyclo-condensation of 1,2-dicarbonyl compounds, substituted aromatic aldehydes,
cycloalkyl amines, and ammonium acetate in ethanol at moderate temperature. Purification of compounds
was performed through a non-chromatographic method. Physical and spectral data analysis
was carried out to characterize the products.
Result: Employing our newly developed L-Pipecolic acid-catalyzed synthetic route, a series of total
twenty-three compounds incorporating 2,4,5-trisubstituted imidazoles (3a-n) and N-cycloalkyl-
2,4,5- trisubstituted imidazoles (4a-i) were synthesized successfully, and a plausible reaction mechanism
is proposed based on the results of the experiment.
Conclusion: All the derivatives were afforded high purity and excellent yields (92–97%) in a short
reaction time (45–90 min). The newly developed synthetic route is rapid and robust and could be
applicable for the synthesis of pharmaceutically active compounds.