Green synthesis of nano zinc ferrite using chicken feet extract and its use as catalyst for the synthesis of 1,3,5-triaryl-4,5-dihydro-1H-pyrazoles

Zinc ferrite type of magnetic nanoparticles (MNPs) could catalyze organic reactions in a mild and environment friendly manner [1-3]. This work described a green and useful method for the preparation of ZnFe2O4 nanoparticles using chicken feet extract. This nano particles used as an efficient nanocatalyst for the synthesis of 1,3,5-triaryl-4,5-dihydro-1H-pyrazoles. The synthesis was carried out via a simple three-component reaction between arylaldehydes, arylmethylketones, and arylhydrazines in good to excellent yields in the precense of nano ZnFe2O4 in solvent-free conditions (Scheme 1). General procedure for the synthesis of 1,3,5-triaryl-1H-pyrazoles 4a. The reaction was carried out by first mixing benzaldehyde 1 (1 mmol, 0.106 g), acetophenon 2 (1 mmol, 0.120 g), and NaOH (1 mmol, 0.040 g) in the presence of ZnFe2O4 magnetic nanoparticles (0.010 mmol, 0.002 g), then phenylhydrazine 3 (1 mmol, 108 g) added to the reaction mixture. After then heating them under microwave irradiation at 600 watts for 1 minute in solvent-free condition. Reaction monitoring by TLC clearly indicated formation of the corresponding 1,3,5-triphenyl-4,5-dihydro-1H-pyrazole 4a. Then ethanol (3 mL) was added to the reaction mixture and then ZnFe2O4 magnetic nanoparticles were separated by a magnet. After that, the product was separated as a light yellow crystalin solution. The solvent was removed and the product was recrystallized from ethanol. The isolated yield was 90%.. In conclusion, We have developed a simple and green method for the synthesis of 1,3,5-triphenyl-4,5-dihydro-1H-pyrazoles in the presence of ZnFe2O4 magnetic nanoparticles under microwave irradiation and Solvent-free conditions. Short reaction times, excellent yields of products, and mild reaction conditions, inexpensive and readily available starting chemicals and catalyst, Eco friendly, use of simple chemicals, and high atomic economy are the main advantages of this method.