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-a]pyrimidines or thiadiazolo[3,2-a]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.