A Novel Cobalt Organic-Inorganic Hybrid Magnetic Nanocatalyst for Convenient Four-Component Synthesis of 3,4-Dihydropyridones

Densely functionalized 3,4-dihydropyridones were synthesized by a four-component reaction of Meldrumʼs acid, ethyl acetoacetate, ammonium acetate, and proper aromatic aldehydes in the presence of novel organic-inorganic cobalt incorporated magnetic nanocatalyst (γ-Fe2O3@HAp/Co(II)) using ethanol as a green solvent at reflux condition. This new synthetic method provided the target compounds in a high yield (70-95%) and lower reaction time (20-75 min). The protocol benefits from the high purity of the products, environmentally friendly, milder reaction conditions, recyclability of the catalyst, and facile workup procedure. The structure of the synthesized novel nanocatalyst was confirmed by FT-IR, XRD, FSEM, TEM, EDS, and TGA analyses. The catalyst was used in eight cycles without any notable variation in catalytic activities.