One-Step, Three-Component Synthesis of Highly Substituted Pyridines Using CuFe2O4@SO3H as Reusable Catalyst

The synthesis of ‘privileged medicinal scaffolds’ is highly important as these compounds oftenact as ligands for a number of functionally and structurally diverse biological receptors,and consequently, serve as a platform for developing pharmaceutical agents for diverse applications.Among them, 2-amino-3,5-dicarbonitrile-6-sulfanylpyridines exhibit various pharmacologicalactivities and are useful as antihepatitis B virus, antiprion, antibacterial, and anticanceragents, and as potassium channel openers for treatment of urinary incontinence. Moreover,some of these compounds were found to be highly selective ligands for adenosine receptors,implicated Parkinson’s disease, hypoxia/ischemia, asthma, kidney disease, and epilepsy.These vast applications have inspired the development of a number of methods for the preparationof pyridine derivatives. however, literature studies reveal that most of the methods involvemultistep sequences and low isolated yields, use of toxic and expensive catalysts, andlack generality. The synthesis of pyridines a through multicomponent reaction (MCR) of aldehydes,malononitrile, and thiols has recently attracted much attention owing to excellentsynthetic efficiency, intrinsic atom economy, high selectivity, procedural simplicity, and environmentalfriendliness [1-3]. In conclusion, we have demonstrated an efficient and generalprocedure for the synthesis of 2-amino-3,5-dicarbonitrile-6-sulfanylpyridines via multicomponentreaction of aldehydes, malononitrile, and thiols using of CuFe2O4@SO3H as a verymild, effective, environmentally benign, and reusable catalyst.