The condensation of aromatic aldehydes and barbituric acid catalyzed by SiO2·12WO3·24H2O in aqueous media at room temperature gave 5-arylidene barbituric acid in high yields with or without the use of ultrasound, providing a simple and efficient route to synthesis of these compounds.
On water catalyst-free synthesis of benzo[d]imidazo[2,1-b] thiazoles and novel N-alkylated 2-aminobenzo[d]oxazoles under microwave irradiation