One-pot synthesis of highly substituted pyrroles using nano copper oxide as an effective heterogeneous nanocatalyst

A convenient one-pot four-component reaction of aromatic aldehydes, β-keto esters and nitromethane in the presence an amine and 10 mol% CuO nanoparticles for the synthesis of highly substituted pyrroles is described. Excellent yields, easily available and less expensive catalyst and easy work-up are the key features of the present method. The NMR spectrum was coupled with quantum chemical calculations in DFT approach using the hybrid B3LYP exchange-correlation functional to confirm the structures of (1-benzyl-4-(4-chlorophenyl)-2-methyl-1H-pyrrol-3-yl)(phenyl)methanone 14 and 1-(1-benzyl-4-(4-chlorophenyl)-2-phenyl-1H-pyrrol-3-yl)ethanone 14′.