Efficient large scale microwave assisted Mannich reactions using substituted acetophenones.

A series of substituted acetophenones, paraformaldehyde, and symmetrical dialkylamines were used in microwave enhanced Mannich reactions. Appropriate reaction conditions in terms of choice of solvent, reaction temperature, and reaction time were studied to allow a fast and reproducible production of Mannich bases. Both small (2 mmol) and large scale reactions (40 mmol) were performed successfully, providing a series of substituted Mannich bases in moderate to high yields and high purity.