Graphitic carbon nitride: a simple and reusable catalyst for one-pot synthesis of 1, 4-dihydropyridine derivatives

1, 4-Dihydropyridines (1,4-DHPs) are important bioactive heterocyclic compounds which possess analgesic, antiviral, antibacterial, and anti-inflammatory activities and represent an abundant structure found in Nature. 1,4-DHPs are generally synthesized using the classical Hantzsch method, through cyclocondensation of an aldehyde, β-ketoesters and ammonia either in acetic acid or in refluxing ethanol for long reaction times that this method typically leads to low yields [1]. Carbon catalysts, which include carbon nanotubes, graphite and graphene, have been used in many industries, including energy storage, the environment and as heterogeneous catalysts in organic reactions. One of the interesting materials that has attracted the attention of many scientists in recent years is carbon nitride, the presence of nitrogen atoms in the carbon framework has led to its high application in various fields of research. Carbon nitrides have several allotropes of which the graphitic phase is the most stable one. Its rich surface features have been attractive for applications in both energy and environment. [2] In this protocol first graphitic carbon nitride nanosheets are prepared using inexpensive materials such as melamine and urea, and after identifid by using spectrscopy such as XRD, SEM, FTIR. In summary, we developed a new protocol for the synthesis of various DHPs derivatives using graphitic carbon nitride as a highly efficient heterogeneous catalyst, which offers significant benefits such as simple work-up procedure, short reaction times, safe and clean conditions, and excellent yields with eco-friendly approach.