Efficient one-pot synthesis of some new pyrimido[5′,4′:5,6]pyrido[2,3-d]pyrimidines catalyzed by magnetically recyclable Fe3O4 nanoparticles

The study is devoted to one-pot reaction of 1,3-dimethylbarbituric acid with aromatic aldehydes and ammonium acetate using Fe3O4 nanoparticles as efficient and magnetically recyclable catalysts. Aromatic aldehydes substituted with electron-withdrawing groups or none, reacted successfully with 1,3-dimethylbarbituric acid and ammonium acetate to give new pyrimido[5′,4′:5,6]pyrido[2,3-d]pyrimidine derivatives (can be also named as pyrido[2,3-d:6,5-d′]dipyrimidines) in high yields over relatively short reaction time. The Knoevenagel condensation products were isolated using aromatic aldehydes bearing electron-donating substituents. The catalyst could be efficiently used for four times without substantial reduction in its activity. The new products were characterized on the basis of FT-IR, 1H NMR and 13C NMR spectral data.