An efficient synthesis of 3,4-dihydorpymidine(1H)-(thio)-ones catalyzed by novel SO3H-functionalized ionic liquids under ultrasound irradiation and solvent free conditions

Novel SO3H-functionalized ionic liquids were successfully applied as catalysts for the one-pot three component Biginelli condensation under ultrasound irradiation without solvent. Various types of 3,4-dihydorpymidine(1H)-(thio)-ones were provided in 84-98% yields and conveniently separated from the reaction mixture by filtration, the dissolved catalyst could be reused with simple treatment. This novel synthetic method is especially favoured because it provides a synergy between ionic liquids and ultrasound irradiation which offers the advantages of high yields, short reaction times, simplicity, and easy workup compared to the conventional methods reported in the literature..