Metal-free three-component assemblies of anilines, α-keto acids and alkyl lactates for quinoline synthesis and their anti-inflammatory activity

A new and metal-free three-component method for the synthesis of 2,4-disubstituted quinolines via the reactions of anilines, α-keto acids and alkyl lactates is reported. The reactions proceed in the presence of p-toluene sulfonic acid (p-TSA) and tert-butyl peroxybenzoate (TBPB) to provide diverse quinoline products via the construction of new CC double, C-C single and CN double bonds without producing any organic mass-based side product. Notably, the anti-inflammatory activity of the quinolines has been investigated by measuring their ability to inhibit NO release by lipopolysaccharide (LPS) induced RAW264.7 cells, leading to the identification of 4i, 4t and 4x as potent anti-inflammatory compounds in vitro.