Carbon Nanomaterials as Efficient Catalysts for Organic Reactions

Carbon based materials such as carbon black (CB), carbon nanotubes (CNTs) and graphene or chemically modified graphenes (CMGs), have been used for various applications in energy storage, electronic, optics, biomedical engineering, medical devices, sensors, etc. Some of these nanomaterials have also been applied in catalysis above all as supports for catalytically active transition metals, thanks to their unique properties such as high surface area, stability and high conductivity. The replacement of environmentally hazardous Brønsted and Lewis acid catalysts with environmentally benign heterogeneous catalysts is currently an intriguing research area and, in this context, the application of nanostructured carbon materials as metal free catalysts for facilitating synthetic organic reactions is a new emerging area with great potential. As part of our research program in developing innovative synthetic methodologies, herein we report the highly efficient activity of some of these nanomaterials as catalysts for condensation reactions with particular attention to the experimental conditions (low impact solvents and very small amounts of catalyst), according to the growing demand for highly sustainable chemical procedures. Interesting aspects such as the recycling and reusability performance of the nanocatalysts were also investigated. Finally, the elaborated methodologies were conveniently exploited for the synthesis of the 1,5-benzodiazepine nucleus, that is a very interesting heterocyclic scaffold with a wide range of application in the pharmaceutical industry.