Ultrasound-promoted solvent-free aza-Michael addition of p-toluenesulfonamide to fumaric esters by potassium carbonate: Synthesis of p-toluenesulfonamide derivatives
An efficient, mild, inexpensive and eco-friendly protocol for the synthesis of p-toluenesulfonamide derivatives by aza-Michael addition reaction of p-toluenesulfonamide to fumaric esters using potassium carbonate under ultrasound irradiation was developed. This method is simple, convenient and the desired compounds are produced in good to excellent yield. The bulkiness of alkoxy group (-OR) of fumaric