Efficient one-pot four-component synthesis of 1,4- dihydropyridines promoted by magnetite/chitosan as a magnetically recyclable heterogeneous nanocatalyst

1,4-Dihydropyridines are synthesized from various aromatic aldehyde, dimedone or 1,3-cyclohexandione, ethyl acetoacetate or methyl acetoacetate and ammonium acetate catalyzed by magnetite/chitosan at room temperature under mild reaction conditions. This process offers an easy and efficient synthesis of 1,4-dihydropyridine derivatives in high yields. The benefits of this protocol are simplicity, nontoxicity, low cost, simple workup, and an environmentally benign nature. The catalyst is recovered by filtration and reused at least five times without significant loss in catalytic activity.