Efficient One-Pot synthesis of hantzsch 1,4- dihydropyridine derivatives using magnetic nickel ferrite nanoparticles as a heterogeneous and reusable catalyst

In recent years, magnetic nanoparticles (MNPs) have emerged as an attracting class of catalysts, because of the increasing need to develop low-cost, green, efficient, and reusable catalysts. Their nano-size property maximizes the contact between reactants and the catalyst, thus mimicking a heterogeneous catalyst. Use of magnetically separable catalysts is one of the most promising strategies. These systems combine the advantages of nanosized catalysts and magnetic properties, thus, providing the opportunity for quantitative recovery of the catalyst by the use of an external magnet, making it cost-effective and potentially applicable for industrial application [1,2]. Quinoline derivatives with 1,4-dihydropyridine scaffolding have pharmacological properties. Some compounds of this family are antimalarial, anti-asthmatic, anti-inflammatory, antibacterial, and tyrosine kinase inhibiting agents. Other researches indicate that 1,4-DHPs express different medical functions as neuroprotectants, having platelet anti-aggregatory activity, cerebral anti-ischemic agents, and chemosensitizers. Also, numerous synthetic methods by MCRs have been reported for the preparation of 1,4-dihydropyridine derivatives under different conditions [3]. In this work, a green, convenient, and environment-friendly approach for the synthesis of biologically active Hantzsch 1,4-dihydropyridine derivatives in the presence of magnetic nickel ferrite nanoparticles, as a heterogeneous and reusable catalyst, has been developed via a one-pot multicomponent reaction of various aldehydes, ethyl acetoacetate and ammonium acetate in solvent-free conditions under microwave irradiation. The proposed methodology is capable of providing the desired products in good to excellent yields and short reaction time with straightforward work-up and a low-cost procedure (Scheme 1).