Fe 3 O 4 @nano-cellulose/Cu(ii): a bio-based and magnetically recoverable nano-catalyst for the synthesis of 4H-pyrimido[2,1-b]benzothiazole derivatives

Abstract

Fe 3 O 4 @nano-cellulose/Cu(ii) as a green bio-based magnetic catalyst was prepared through in situ co-precipitation of Fe 2+ and Fe 3+ ions in an aqueous suspension of nano-cellulose. The mentioned magnetically heterogeneous catalyst was characterized by FT-IR, XRD, VSM, FESEM, TEM, XRF, EDS and TGA. In this research, the synthesis of 4H-pyrimido[2,1-b]benzothiazole derivatives was developed via a three component reaction of aromatic aldehyde, 2-aminobenzothiazole and ethyl acetoacetate using Fe 3 O 4 @nano-cellulose/Cu(ii) under solvent-free condition at 80 °C. Some advantages of this protocol are good yields, environmentally benign, easy work-up and moderate reusability of the catalyst. The product structures were confirmed by FT-IR, 1 H NMR, and 13 C NMR spectra.