Microwave- and ultrasound-assisted heterocyclics synthesis in aqueous media

Abstract In green chemistry, the concept of environmentally friendlier preparations of organic substances is always accompanied by the concept of energy and resources saving, either by optimizing reaction conditions or introducing new technologies. The use of water approach is among these technologies. However, in terms of energy-saving and optimization of reaction conditions, the Microwave (MW) and Ultrasound (US) technologies have now proved to be important tools and real options in chemical reaction activations. This chapter discusses some laboratory and industrial applications of each of these types of activations in heterocyclic compounds synthesis. In particular, MW, as well as US-assisted organic reactions in water, has been regarded as one of the green methodologies, simple and valuable tools among the synthetic community. The discussion will show that the use of these benign techniques in water shows alternative methods to circumvent the problems associated with the issues of solubility, while at the same time enhancing reaction efficiency. The use of aqueous catalytic systems, along with high technology instruments such as MW and US, offers a fruitful approach in achieving green, high-yielding reactions and also contributes to the development of benign techniques in heterocyclic synthesis.