Efficient novel eutectic-mixture-mediated synthesis of benzoxazole-linked pyrrolidin-2-one heterocycles

Abstract In this study, new benzoxazole-linked pyrrolidinone heterocyclic compounds were synthesized by an eco-efficient strategy using substituted benzylamines and 2-aminophenol under ultrasonic irradiation in the presence of a newly designed metal-free deep eutectic solvent (DES). This DES was prepared by using a eutectic mixture of urea and a synthesized glycine-derived ionic liquid. X-ray diffraction and infrared spectroscopy were employed to investigate the structure of the ionic liquid and characterize the DES, respectively. This method exhibited key advantages of high productivity, a short reaction time, and simple processing. Moreover, this DES was easily separated from reaction mixtures and can be recycled for multiple reactions.