This review surveys the major structural features in various groups of small molecules that are considered to be antioxidants, including natural and synthetic compounds alike. Recent advances in the strategic modification of known small molecule antioxidants are also described. The highlight is placed on changing major physicochemical parameters, including log p, bond dissociation energy, ionization potential, and others which result in improved antioxidant activity.

Recent advances in the application of heterogeneous catalysis combined with microwave irradiation in the synthesis of heterocyclic compounds are reviewed. While a detailed summary of the different catalysts applied in the synthesis of heterocycles is provided, the work mainly focuses on the heterocyclic compounds and their synthesis and not the preparation or characterization of the catalyst. Due to the large number of N-containing heterocycles, the synthesis of these compounds dominates this account, however, the preparation of other heteroatom containing compounds is also covered in detail. The literature data are summarized based on the size of cycles and the number of heteroatoms in the compounds. Since the major goal of the work is to highlight the environmentally benign and sustainable nature of the combined microwave-assisted heterogeneous catalytic methods, the green aspects of the individual synthetic approaches will be emphasized.

A solid acid-catalyzed microwave-assisted synthesis of substituted quinolines is described. The quinolines were synthesized by a multicomponent domino reaction of anilines, aldehydes and terminal aryl alkynes. The synthetic pathway involves the formation of an imine, followed by the intermolecular addition of an alkyne to the imine. This intermediate immediately undergoes ring closure and oxidative aromatization. The reaction is catalyzed by montmorillonite K-10, a strong, environmentally benign solid acid. The multicomponent approach yields the products with nearly 90% atom economy in excellent yields in a matter of minutes. The use of microwave activation reduces the reaction time significantly.

Recent advances in the application of microwave-assisted heterogeneous catalytic synthesis approaches are reviewed with additional inputs on the energy efficiency and scale-up of microwave-assisted synthesis.

A catalyst and solvent-free room temperature synthesis of pyrroles is described.