ZrOCl2·8H2O: An efficient and reusable catalyst for the synthesis of imidazolines and bis-imidazolines under various reaction conditions

Efficient preparation of 2-imidazolines and bis-imidazolines by reaction of ethylenediamine with nitriles in the presence of catalytic amounts of zirconyl chloride (ZrOCl2·8H2O) as a reusable catalyst under reflux conditions is reported. Sonication of this system enhanced the catalytic activity of zirconyl chloride and this was led to higher product yields and shorter reaction times. When this catalytic system was exposed to microwave irradiation, the reaction times were reduced up to 10 min and the yields increased to 96%. Another advantage of the systems, under ultrasonic and MW irradiation, is the ability to carry out large-scale reactions. In three cases, the catalyst was reused several times without loss of its activity.

Graphical abstractEfficient preparation of 2-imidazolines and bis-imidazolines by reaction of ethylenediamine with nitriles in the presence of catalytic amounts of ZrOCl2·8H2O as a reusable catalyst under reflux conditions, MW and under ultrasonic irradiation is reported. Figure optionsDownload full-size imageDownload as PowerPoint slide