Construction of MWCNTs/MNPs-Based Copper Nanocomposite as an Efficient and Reusable Catalyst for Four-Component Preparation of Highly Substituted Pyridines

A sustainable and highly efficient four-component protocol has been established for the synthesis of structurally diverse and highly substituted pyridine derivatives. The catalytic system, MWCNTs/MNPs–Tris(2-aminoethyl)amine–CuCl₂, effectively promotes the one-pot condensation of aromatic aldehydes, malononitrile, ethyl acetoacetate, and substituted anilines in aqueous medium under reflux conditions. This green catalytic method provides the desired pyridines in excellent yields (86–98%) within 1 h, highlighting its remarkable activity and selectivity. The reaction system exhibits wide substrate compatibility, tolerating both electron-donating and electron-withdrawing substituents on the aromatic rings. Product identity and purity were confirmed by melting-point determination and observation of crystalline or oily characteristics. A comparative evaluation with existing protocols demonstrates significant advantages in yield, environmental compatibility, and operational simplicity. The use of water as an environmentally benign solvent, along with the recyclable magnetic nanocatalyst, underscores the method's sustainability and reusability. Overall, this approach provides a green, rapid, and practical route to valuable pyridine-based heterocycles with potential biological relevance.