An efficient one-pot synthesis process for preparing 2-imidazolines from aldehydes and ethylenediamine using molecular iodine and potassium carbonate in absolute ethanol at 25–30°C under ultrasound irradiation is described. The synthetic strategy has the following advantages: mild conditions and low costs requirements, readily available catalyst, short reaction times, simplicity of operation, and good-to-excellent yields.
Different types of 2-imidazolines, bis-imidazolines, and N-substituted-2-imidazolines are efficiently oxidized to their corresponding imidazoles with potassium permanganate (KMnO4) supported on montmorillonite K-10 under very mild conditions. The procedure is very simple and no strict conditions were required. Selective dehydrogenation of 2-alkyl-2-imidazolines in the presence of 2-aryl-2-imidazolines is a noteworthy advantage of this method and can be considered as a useful practical achievement in these reactions.Key words: 2-imidazolines, imidazoles, dehydrogenation, potassium permanganate, montmorillonite K-10.