Covalently Anchored Sulfonic Acid on Silica Gel as an Efficient and Reusable Heterogeneous Catalyst for the One-Pot Synthesis of Hantzsch 1,4-Dihydropyridines under Solvent-Free Conditions
Raman Gupta, Rajive Gupta, Satya Paul*, Andre Loupy
*Department of Chemistry, University of Jammu, Jammu-180 006, India, Email: paul7rediffmail.com
R. Gupta, R. Gupta, S. Paul, A. Loupy, Synthesis, 2007, 2835-2838.
A highly efficient one-pot synthesis of Hantzsch 1,4-dihydropyridines is catalyzed by sulfonic acid covalently anchored onto the surface of silica gel. All types of aldehydes, including aromatic, unsaturated, and heterocyclic aldehydes, gave excellent yields. The heterogeneous silica gel/sulfonic acid catalyst can be recycled without significant loss of activity.
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