Rapid and efficient synthesis of poly-substituted quinolines assisted by p-toluene sulphonic acid under solvent-free conditions: comparative study of microwave irradiation versus conventional heating.

A rapid and efficient method for the preparation of various poly-substituted quinolines has been developed through the Friedländer condensation of 2-aminoarylketone or 2-aminoarylaldehyde with carbonyl compounds in the presence of p-toluene sulphonic acid, which was achieved by both microwave irradiation and conventional heating under solvent-free conditions.