A new role for solar energy as a renewable energy source for catalyst-solvent free gram-scale synthesis of pyrano[2,3-d]pyrimidine scaffolds

Abstract

In the realm of chemistry, increased energy consumption as a result of population development and industrialisation necessitates the usage of renewable energy sources. Nonrenewable energy sources emit not only greenhouse gases but also other toxic pollutants that harm all living creatures. This clearly necessitates the employment of an ecologically acceptable and cost-effective renewable energy source by the researchers. The Knoevenagel-Michael cyclocondensation of aldehyde derivatives, malononitrile, and barbituric acid/1,3-dimethylbarbituric acid via a three-condensation domino reaction can be used to create pyrano[2,3-d]pyrimidine scaffolds. This study establishes solar energy as a novel renewable energy source for the synthesis of pyrano[2,3-d]pyrimidine scaffolds under catalyst-solvent-free conditions, with excellent yields, reaction time savings, and atom economy. This reaction was carried out on a range of substrates with the use of a renewable energy source (sunlight) and a relatively simple experimental setup. The reaction was extremely fast, and there was no need for a solvent or chromatographic purification. According to a multigram scale reaction of model substrates, this reaction might be scaled up without affecting the outcome. Furthermore, the approach's broad applicability was proved by its usage to synthesis real-world pharmaceutical molecules.