Green Solvent-Free Synthesis of Biologically Relevant Heterocycles—A Mini Review

There has been a significant increase in the development of synthetic strategies to obtain various heterocyclic moieties. This area of research is particularly attractive because many heterocycles exhibit biological activity. Conventional techniques often involve the use of volatile organic solvents, which are typically flammable, toxic, and environmentally hazardous. These solvents are now being replaced either with greener alternatives or by completely eliminating their use. Numerous solvent-free methods for the synthesis of bioactive heterocyclic compounds have already been reported in the literature. This mini-review highlights recent advances in solvent-free synthetic methods for the preparation of diverse heterocycles with various biological activities.