Nano-cellulose/BF3/Fe3O4: a magnetic bio-based nano-catalyst for the synthesis of pyrimido[2,1-b]benzothiazoles under solvent-free conditions

Nano-cellulose/BF 3 /Fe 3 O 4 is a bio-based and eco-friendly catalyst with high catalytic activity. Easy separation with an external magnet and recyclability without significant loss of its activity are some advantages of this catalyst. Nano-cellulose/BF 3 /Fe 3 O 4 was characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray fluorescence, vibrating sample magnetometry, thermogravimetric analysis, and BET theory. The catalyst was applied for the synthesis of 4 H -pyrimido[2,1- b ]benzothiazole derivatives via one-pot condensation of aldehydes, 2-aminobenzothiazol and ethyl acetoacetate, under solvent-free conditions at 100 °C. This method offers several advantages including easy work-up, excellent yields and short reaction time. Graphical Abstract