Multicomponent reactions leading to symmetric and asymmetric multi-substituted 1,4-dihydropyridines on montmorillonite

Highly functionalized multi-substituted symmetric and asymmetric 1,4-dihydropyridines were concisely synthesized in moderate to good yields via one-pot multicomponent reactions (MCRs) of β-dicarbonyl compounds, aldehydes and amines at room temperature on montmorillonite. The merits of this method include the environmentally friendly reaction conditions, simple operation, broad substrate, satisfied yields and the reuse of the montmorillonite.