CoFe2O4@SiO2@APTES@HO-PBA@Cu(OAc)2: A highly efficient and recyclable nanocatalyst for one-pot synthesis of multifunctional 1,5-benzodiazepines via three-component domino reaction

Abstract

CoFe2O4@SiO2@APTES@HO-PBA@Cu(OAc)2: A magnetic core-shell copper-based nanocatalyst was successfully prepared. The fabricated nanocatalyst was structurally authenticated using various analytical techniques such as FT-IR, XRD, SEM, TEM, EDS, ICP-AES, TGA/DTA, XPS, BET, and VSM. The highly proficient catalyst proved its dependability for one-pot synthesis of diester/methyl-substituted polycyclic fused 1,5-benzodiazepines via three-component domino reaction of nucleophilic addition and elimination, Michael addition, C–C cross-coupling reactions, and H proton transfer reaction in good to excellent yields. Also, all products were obtained in high TON (up to 17,241) and TOF (up to 4816), which reveals the nanocatalyst has high activity and selectivity in described domino reactions. The suggested mechanism for one-pot synthesis of diester/methyl-substituted polycyclic fused 1,5-benzodiazepines in the presence of copper-based nanocatalyst was also proposed, respectively. The nanocatalyst can be reused seven times without significant loss of its catalytic efficiency. The easy recovery of the nanocatalyst and reusability, broad substrate scopes, short reaction time, high yields of products, and mild conditions make this protocol practical, environmentally friendly, and economically attractive.