Rapid and cleaner synthesis of 1,4‐dihydropyridines in aqueous medium

The present investigation deals with a novel water soluble Lewis acid complex, Zn[(L)proline]2 catalyzed Hantzsch 1,4‐dihydropyridine derivatives syntheses in aqueous medium assisted by microwave irradiation. The microwave promoted syntheses in aqueous medium afforded moderate to excellent yield (up to 98%) within short reaction time and allowed the reaction to take place with low microwave power (200 W). This synthetic methodology provides easier separation of products and the catalyst exhibits recycling ability without loss of its catalytic activity up to five reaction cycles.