Ultrasound and deep eutectic solvent (DES): A novel blend of techniques for rapid and energy efficient synthesis of oxazoles

The present work deals with the synthesis of novel oxazole compounds by using effective combination of ultrasound (US) and deep eutectic solvent (DES). The reaction was also conducted by thermal method (NUS) and the comparative studies are provided. It was observed that applying ultrasound not only improved yields and reduced reaction times but also saved more than 85% energy as shown by energy consumption calculations. The advantages of using DES as reaction medium is highlighted from the fact that it is bio-degradable, non-toxic, recyclable and could be easily prepared using inexpensive raw materials. The recyclability for DES was studied wherein it was found that ultrasound has no negative effects on DES even up to four runs. In addition, the present work is the first report on the combinative use of DES and US in organic synthesis.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► First organic synthesis using blend of Ultrasound with deep eutectic solvent (US-DES). ► Energy efficient method saving more than 85% energy. ► Novel oxazole derivatives were synthesized using this method. ► Recyclability studies of DES revealed its stable nature in ultrasound. ► US-DES technique is an efficient alternative to conventional method.