Multifunctional Deep Eutectic Solvent-Catalyzed Synthesis of Dihydropyrimidinethiones: A Sustainable Approach for Green and Efficient Reactions

Abstract

Background: This study investigates the synthesis of dihydropyrimidinethiones using a multifunctional deep eutectic solvent (DES) composed of Choline chloride (ChCl) and ammonium thiocyanate. This DES serves as a catalyst, solvent, and reagent, providing a simple, highyielding, and environmentally friendly method for dihydropyrimidinethione synthesis. The use of DES in this capacity offers several advantages, including reduced environmental impact, high efficiency, and ease of use, highlighting its potential as a sustainable alternative in organic synthesis. Objective: The objective of this study is to investigate the application of a deep eutectic solvent (DES) composed of ChCl and ammonium thiocyanate as a catalytic solvent and reagent system for synthesizing dihydropyrimidinethiones. The aim is to simplify the reaction setup, improve yields, and enhance the green metrics of the process. Methods: ChCl and ammonium thiocyanate were combined to form a DES catalyst-solvent system. Dihydropyrimidinethiones were synthesized in one-pot reactions at ambient temperature. Green metrics and DES recovery were evaluated. Comparative analysis with traditional methods was conducted. Results: The DES efficiently catalyzed dihydropyrimidinethione synthesis with high yields. Simplified reaction setup, safe solvent properties, and favorable green metrics. DES was recoverable and reusable, outperforming traditional methods in efficiency and eco-friendliness. Conclusion: The ChCl and ammonium thiocyanate DES demonstrated remarkable efficiency and eco-friendliness in dihydropyrimidinethione synthesis. The toxicity-free, multifunctional roles of the DES, serving as a catalyst, solvent, and reagent, highlight its novelty and potential as a sustainable alternative in organic chemistry. This study simplifies the synthesis process and improves yields and green metrics, showcasing the DES as a promising candidate for future research and industrial applications.