A facile route to access N-heterocycles using a choline chloride–ethylene glycol-based DES in a dual role

A green, metal-free, efficient, and simple methodology has been described for the synthesis of a series of biologically and pharmaceutically important nitrogen heterocycles. A variety of 1,3-benzazole compounds are obtained in good to excellent yields by the one-pot reaction between 2-amino/hydroxy/mercaptoanilines with benzylamines under solvent-free conditions using a choline chloride (ChCl)-ethylene glycol (EG) (1 : 2) DES. The inexpensive, biodegradable ChCl-EG (1 : 2) DES plays the dual role of a solvent and catalyst. The DES is recyclable and can be used several times without any significant loss of its activity.