Nano magnetite obtained from the oxidative precipitation supporting Brønsted ionic liquid as catalyst for the synthesis of thiazolo- or thiadiazolo-[3,2-<i>a</i>]pyrimidines

Magnetic iron oxide nanoparticles produced via the oxidative precipitation of only FeSO₄·7H₂O were used as a solid support to immobilize Brønsted acidic ionic liquid to afford Fe₃O₄@O₃Si[PrMIM]HSO₄. The solvent-free synthesis of thiazolo[3,2-<i>a</i>]pyrimidines or thiadiazolo[3,2-<i>a</i>]pyrimidines via the three-component reaction of 2-aminothiazoles or 2-aminothiadiazoles, aromatic aldehydes, and ethyl acetoacetate afforded high yields in the range of 57–93% during 2–11 h. In addition, Fe₃O₄@O₃Si[PrMIM]HSO₄ has demonstrated stability, efficiency, ease of recovery with a yield of 98%, and strong recyclability throughout seven catalyst recycles without remarkable yield reduction. The catalyst has been characterized by the use of XRD, IR, VSM, EDX, FE-SEM, TEM, and TGA.