Ultrasound-assisted synthesis of 2,5-dimethyl-N-substituted pyrroles catalyzed by uranyl nitrate hexahydrate

An efficient synthesis of different novel 2,5-dimethyl-N-substituted pyrrole derivatives by the Paal–Knorr condensation has been accomplished using uranyl nitrate hexahydrate as catalyst under soft conditions and ultrasonic irradiation. The synthesized compounds were confirmed through spectral characterization using IR, 1H NMR, 13C NMR and mass spectra.

► Paal-Knorr reaction using UO2(NO3)2·6H2O as a catalyst under ultrasonic irradiation.
► Advantages: operation simplicity, high yields, less reaction times, easy workup.
► Pyrroles with different N-substituted heterocyclic moieties were synthesized.