A Cu-catalyzed three-component N-alkylation coupling reaction of N-heteroarenes with methyl ketones and DMPA as a carbon source has been developed. Using methyl ketones as alkylation reagents and DMPA (N,N'-dimethylpropionamide) as a carbon source, the reaction proceeded smoothly under the Cu-based oxidative system and led to a series of functionalized N-heterocycles including 4-quinazolinones, triazoles and pyrazoles.