l-Proline as an efficient enantioinduction organo-catalyst in the solvent-free synthesis of pyrazolo[3,4-b]quinoline derivatives via one-pot multi-component reaction

Abstract

The role of L-proline as an efficient organo-catalyst for the three-component synthesis of pyrazoloquinolinones involving dimedone, 3-methyl-1H-pyrazol-5-amine and various aryl aldehydes under mild solvent-free condition is reported. Besides the several advantages offered by this method such as its generality, simplicity, high yields and environment friendly reaction, the most notable is the ability of the catalyst to influence asymmetric induction in the reaction. Interestingly, it was observed that in addition to being an efficient catalyst, L-proline also imparted enantioselectivity in the synthesised pyrazoloquinolinones derivatives.