Ultrasound for Drug Synthesis: A Green Approach

This last century, the development of new medicinal molecules represents a real breakthrough in terms of humans and animal life expectancy and quality of life. However, this success is tainted by negative environmental consequences. Indeed, the synthesis of drug candidates requires the use of many chemicals, solvents, and processes that are very hazardous, toxic, energy consuming, expensive, and generates a large amount of waste. Many large pharmaceutical companies have thus moved to using green chemistry practices for drug discovery, development, and manufacturing. One of them is the use of energy-efficient activation techniques, such as ultrasound. This review summarizes the latest most representative works published on the use of ultrasound for sustainable bioactive molecules synthesis.

Ultrasound assisted the green synthesis of 2-amino-4H-chromene derivatives catalyzed by Fe3O4-functionalized nanoparticles with chitosan as a novel and reusable magnetic catalyst

Fe3O4 nanoparticles were prepared by chemical coprecipitation method. Subsequently immobilization of chitosan on Fe3O4 nanoparticles was accomplished and afforded magnetic Fe3O4-chitosan nanoparticles. Synthesized nanoparticles was found to be a magnetic and heterogeneous catalyst for a one-pot and efficient synthesis of 2-amino-4H-chromenes by condensation of aldehydes with malononitrile and resorcinol under ultrasound irradiation as an ecofriendly method. This convenient procedure allowed us to achieve products under ultrasound irradiation in short time and excellent yield without using of harmful catalyst. The present method will permit a further increase of the diversity within the 2-amino-4H-chromene family.