Lys-CQD catalyzed synthesis of thiourea, amide, and formamide compounds using renewable and competitive feedstocks

Abstract

The use of renewable and cheap precursors in chemical synthesis is highly beneficial, yet challenging due to their inert chemistry and the need for complex catalysts to enhance their reactivity. Herein, we demonstrate that a lysine-modified carbon quantum dot (Lys-CQD) catalyst is a promising catalyst for activating various carbonyl sources. Initially, in a one-pot 3-step reaction, Lys-CQD promoted the reaction of anilines with CS₂ toward the synthesis of thioureas. The reaction was performed in a choline chloride/urea deep eutectic solvent (ChCl/U DES), which also served as a urea-bearing precursor. Moreover, in the reaction of anilines with DMF, Lys-CQD proved to be a potent catalyst for synthesizing formamide products. Notably, DMF functioned as both the solvent and the carbonylation precursor. Lastly, the Lys-CQD-catalyzed reaction of various amines with vinyl acetate was exploited, furnishing different amides with high yields, including amide-containing drugs such as acedoben. The results highlight the strong potential of Lys-CQD as a clean catalyst for organic synthesis, particularly in activating unreactive carbonyl precursors.