Nano-Fe3O4@SiO2–TiCl3 as a novel nano-magnetic catalyst for the synthesis of 4H-pyrimido[2,1-b]benzothiazoles

Fe 3 O 4 @SiO 2 –TiCl 3 NPs, a novel core shell catalyst, was synthesized via preparing Fe 3 O 4 @SiO 2 as a magnetic support followed by treatment with titanium tetrachloride (TiCl 4 ). The structure, morphology and magnetic properties of this catalyst were recognized by different techniques including Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry as well as thermo-gravimetric analysis. To consider the catalytic activity of this magnetic catalyst, it was used in a multicomponent reaction between 2-aminobenzothiazole, aldehydes and ethyl acetoacetate to synthesize 4 H -pyrimido[2,1- b ]benzothiazole derivatives. Our results indicated that the compounds were synthesized with high yield and purity in a short reaction time. Furthermore, the obtained results indicated that this catalyst can be reused for at least three times without no significant change in the efficiency. Graphical Abstract