A heavy metal- and oxidant-free, one-pot synthesis of pyridines and fused pyridines based on a Lewis acid-catalyzed multicomponent reaction.

The InCl3-catalyzed sequential multicomponent reaction between 2-furfurylamine, β-dicarbonyl compounds and α,β-unsaturated aldehydes in ethanol, followed by microwave irradiation in solvent-free conditions, afforded good to excellent yields of highly substituted pyridines, with loss of a 2-furylmethyl side chain. The method was also adapted to the synthesis of quinolones, isoquinolines, phenanthridines and more complex fused pyridine systems.