Trash to Treasure: Eco-Friendly and Practical Synthesis of Amides by Nitriles Hydrolysis in WEPPA

Synthesis of bioactive scaffolds catalyzed by agro-waste-based solvent medium

The backbone of synthetic organic chemistry is the formation of carbon–carbon and carbon–heteroatom bonds. Scientists are actively working to develop new methods of bond-forming reactions because it is one of the most useful tools for the development of structurally diverse molecular entities. On the other hand, scientists are constantly discovering chemical processes to make them more sustainable in order to avoid the ever-increasing chemical emission associated with hazards to the environment. Thus, the development of greener catalytic reactions demonstrated a massive uptick in the ability to carry out carbon–carbon and carbon–heteroatom bond-forming reactions under environmentally friendly and simple reaction conditions. Various approaches are demonstrated, namely, solvent-free, microwave irradiation, ionic liquids, ball milling, ultrasound, one-pot, and aqueous-mediated methods under green chemistry protocol. Agro-waste is the postharvest part or agricultural residues derived from various agricultural activities, which has diverse scope and applications. The use of this agro-waste is an eco-friendly and cost-effective process of waste management. Appropriate and optimal utilization of these waste by-products is one of the major challenges in the present days. The recent trend around the globe is to transform waste into wealth concepts to achieve various applications. Agro-waste-derived ashes and extracted medium are successfully studied recently as a heterogeneous- or homogenous-based catalyst in various organic transformations. Agro-waste-derived catalysts are easily available, cost-effective, simple to prepare, nontoxic, easy to handle, biodegradable, and more environmentally benign. This article focuses more on a few instances of agro-waste-based homogeneous and heterogeneous organic synthesis, especially those used in the construction of bioactive molecule synthesis via C–C and C–X bond formation reactions are discussed. The compiled literature in this article is based on keywords used in the search engine on “agro-waste-based catalyst for organic transformations”, and review articles published on this topic, future scope, and summary are discussed.

Water extract of red mud: an efficient and renewable medium for environmentally benign synthesis of 2-amino-4H-chromenes

In this study, an efficient and convenient domino Michael addition/intramolecular cyclization protocol is presented for the synthesis of biologically relevant 2-amino-4H-chromenes in short reaction times using water extract of red mud (WERM) at room temperature. Red mud is generated abundantly as wastes in aluminum industries and this is the first report to utilize WERM as an effective and renewable medium in organic synthesis. As the precursor material is a waste, the present method is environmentally benign and economical. The final 2-amino-4H-chromenes were obtained in high yields by simple precipitation and subsequent washing by aqueous ethanol which eliminates the chromatographic separation. The present method is tolerated by electronically diverse functional groups and also applicable for large-scale synthesis. Moreover, WERM was recovered from the reaction medium and reused for several cycles without significant loss of reactivity.