TETRABUTYLAMMONIUM HEXATUNGSTATE [TBA]2[W6O19]: A NOVEL HETEROGENEOUS CATALYST FOR ONE-POT SYNTHESIS OF HANTZSCH 1,4-DIHYDROPYRIDINES IN SOLVENT-FREE

摘要

A new method for one pot synthesis of Hantzsch 1,4-dihyropyridines was achieved by the reaction of aromatic aldehydes, ethyl acetoacetate and ammonium acetate at 80 °C in the presence of an isopoly tungstate ,tetrabutylammonium hexatungstate [TBA]2[W6O19], as an effective and environmentally friendly catalyst. An important advantage of this catalyst is the ease of separating it from the reaction mixture, as well as the fact that it could be recycled a number of times.