Boronic acid functionalized silica‐coated Fe₃O₄ as a novel magnetically separable catalyst for the synthesis of hydrazinyl thiazoles

Abstract

A novel silica‐coated magnetite supported boronic acid functionalized nanocatalyst (Fe3O4@SiO2‐Pr‐N=CH‐C6H4B[OH]2) was synthesized using a simple synthetic protocol. The catalyst was fully characterized by using Fourier transform‐infrared (FT‐IR), X‐ray diffraction (XRD), energy dispersive X‐ray (EDX), thermogravimetric analysis‐differential thermal analysis (TGA‐DTA), field emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM) techniques. The structural investigations revealed that the catalyst is nano‐sized (average crystallite size 13 nm), spherical, thermally stable, and magnetic in nature having a magnetic saturation of 51.26 emu/g. The catalytic activity of Fe3O4@SiO2‐Pr‐N=CH‐C6H4B(OH)2 was explored in the synthesis of hydrazinyl thiazoles via one‐pot, three‐component reaction of phenacyl halide, thiosemicarbazide and aryl aldehyde in EtOH:H2O (50:50, v/v) at room temperature and it gave above 90% yields of hydrazinyl thiazoles. The catalyst being magnetically separable can be reused six times with the retention of catalytic activity. The present approach offers the advantages of operational simplicity, shorter reaction time, ambient reaction condition, facile separation of catalyst, and higher yields of the products.