MICROWAVE-PROMOTED SYNTHESIS OF 3,4-DIHYDROPYRIMIDIN-2(1H)-(THIO)ONES USING IL-ONO AS RECYCLABLE BASE CATALYST UNDER SOLVENT-FREE CONDITIONS

A mild, efficient, and solvent-free microwave (MW)-promoted Biginelli reaction for the synthesis of 3,4-dihydropyrimidin-2(1H)-(thio)ones in nitrite ionic liquid (IL-ONO) is described. This ionic liquid is a weak Lewis base catalyst, which can be easily recovered and reused in several runs. The satisfactory results were obtained with good yields and short reaction time, using a simple experimental procedure.