One‐Pot Synthesis of Benzo[4,5]imidazo[1,2‐a]pyrimidin‐2‐ones Using a Hybrid Catalyst Supported on Magnetic Nanoparticles in Green Solvents

The conversion of soluble polyoxometalate into insoluble polyoxometalate is considered to be one of the major challenges in synthetic organic chemistry. Here, polyoxometalate was bonded to the salt part of an organic branch immobilized on the silica‐coated Fe(3)O(4) nanoparticle and characterized using various techniques. The fabricated complex was used as a heterogeneous catalyst in a novel one‐pot reaction for synthesis of benzo[4,5]imidazo[1,2‐a]pyrimidin‐2‐ones using aromatic amines, dimethyl acetylenedicarboxylate (DMAD), derivatives of benzaldehyde and 2‐aminobenzimidazole in water/ethanol as a green solvent. 21 derivatives of benzo[4,5]imidazo[1,2‐a]pyrimidin‐2‐one were synthesized by this method and fully characterized. The high stability of the catalyst showed that it can be reused for 6 times without decreasing in activity. The combination of new synthetic method, new ferromagnetic heterogeneous nano‐catalyst, green solvent and simple separation method were presented in this work.