Synthesis of pyrrolidones and quinolines from the known biomass feedstock levulinic acid and amines

Abstract

The catalytic conversion of biomass-derived compounds into value-added products such as food additives, agrochemical components, and pharmaceutical formulations, is a promising and cost effective synthetic strategy. Here, we describe the synthesis of a variety of N-(alkyl, aryl)-5-methyl-2-pyrrolidones through the reductive amination of levulinic acid using formic acid as the hydrogen source. This system is catalyzed by 3.8nm ruthenium nanoparticles that were prepared by thermal decomposition of [Ru3(CO)12] in solvent-free conditions. When the reactions were carried out without the catalyst, the pyrrolidones were obtained with low yield and poor selectivity. In addition, the reaction between levulinic acid and 2-ethynylaniline produced 2-(2,4-dimethylquinolin-3-yl) acetic acid (8) in mild and metal-free conditions with good yield. Furthermore, the synthesis of substituted quinolines was achieved through a condensation reaction between levulinic acid and different 2-alkynylanilines promoted by p-toluenesulfonic acid, this method is highlighted as a novel procedure for the preparation of quinolines.