Magnetic sodium alginate: An efficient Nanocatalyst for the one-pot synthesis of substituted imidazoles and benzimidazoles

Magnetic sodium alginate was shown to be a highly active and efficient recyclable catalyst for three-component synthesis of imidazole derivatives from benzoin, different aldehydes and ammonium acetate under mild reaction conditions in short reaction times and good to excellent yields in EtOH. Also, benzimidazole derivatives were efficiently prepared from ophenylenediamine and different aldehydes in the presence of magnetic sodium alginate . Moreover, the catalyst was also recovered and reused at least four times without significant decrease in its reactivity. The magnetic sodium alginate catalyst was characterizred by fourier transformer infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD) and nitrogen adsorption–desorption isotherms (NADI) techniques as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Compared to the classical methodologies, this method illustrated the advantages including low loading of the catalyst, short reaction times, high to excellent yields, easy separation and purification of the products, and reusability of the catalyst. Imidazole and benzimidazole molecules are important substructures in a number of molecules which exhibit an array of biologic and pharmacological activities. The imidazole ring system is an important constituent of numerous natural products and medicinally important compounds, such as Cimetidin, which acts as antiulcerative agent. Omeprazole a proton pump inhibitor, and the benzodiazepine antagonist flumazeni. A platelet coagulation drug in animal and human beings, trifenagre, is a 2, 4, 5 trisubstituted aryl-1H-imidazole derivative.