Sulfonic Acid Functionalized Silica: An Efficient Heterogeneous Catalyst for a Three-Component Synthesis of 1,4-Dihydropyridines under Solvent-Free Conditions
Sulfonicacidfunctionalized silica catalyzed the three-component reaction of aromatic amines, alpha,beta-unsaturated aldehydes and beta-keto esters forming the corresponding 1,4-dihydropyridines in short reaction times and in high yields.