Eco-Friendly Bio-Based Solvents for the Acetylation of the Amino Group of Amino Acids

Nature-derived products, like juices and peel extracts of fruits and vegetables, have emerged in recent years as interesting and sustainable alternatives to traditional solvents in several synthetic applications. Herein, we present a green and fast method for the N-acetylation of amino acids, using several bio-based solvents (vinegar, tomato/kiwi/apple peel extracts, lemon juice, etc.). The high reactivity of the amino group is often a limitation in synthetic processes, making its protection a necessary step to achieve pure products and limit side reactions. Therefore, versatile, time-efficient procedures, minimal purification efforts, and good yields are desirable features for these transformations. Our new method meets all these criteria, offering a valuable and eco-friendly alternative to traditional approaches. In detail, we managed to obtain comparable yields to established setups, while improving safety and reducing the environmental impact of the overall process. Most notably, the milder conditions made it possible to avoid the use of running water (saving about 250 L/reaction) and electric-powered cooling devices.