Multicomponent Domino Cyclization-Oxidative Aromatization on a Bifunctional Pd/C/K-10 Catalyst: An Environmentally Benign Approach toward the Synthesis of Pyridines

A one-pot synthesis of substituted pyridines via a domino cyclization-oxidative aromatization (dehydrogenation) approach is described. The process is based on the use of a new bifunctional noble metal-solid acid catalyst, Pd/C/K-10 montmorillonite and microwave irradiation. The cyclization readily takes place on the strong solid acid while palladium dehydrogenates the dihydropyridine intermediates to the desired products.