A Robust Nanocatalyst Incorporating Multi‐Walled Carbon Nanotubes Infused with Magnetic Nanoparticles and Biguanide–Silver Nanoparticles for Multicomponent Synthesis of Benzopyrano‐Pyrimidines

A highly efficient and environmentally friendly synthetic method has been developed for the preparation of benzopyrano-pyrimidines using multi-walled carbon nanotubes/magnetic nanoparticles-Biguanide-Ag NPs as a heterogeneous nanocatalyst in choline chloride-urea (ChCl-Urea) deep eutectic solvent. This approach offers numerous advantages, including high isolated yields (86-99%) and short reaction times (10-70 min), along with broad substrate compatibility for both electron-donating and electron-withdrawing functional groups. The method exhibits excellent catalytic efficiency, with high turnover numbers and turnover frequencies, even at low catalyst loading. The use of ChCl-Urea as a green, biodegradable, and nonvolatile solvent aligns with sustainable chemistry principles and allows for easy solvent recovery. Additionally, the magnetic nanocatalyst is easily recoverable and reusable, maintaining activity over multiple cycles. Operational simplicity, mild conditions, and one-pot multi-component reaction design further enhance the method's scalability and synthetic utility. Given the biological relevance of benzopyrano-pyrimidines, this strategy presents a valuable platform for green synthesis in medicinal chemistry and pharmaceutical development.