ABSTRACT
A protocol that carboxylic acids esterifies with the quaternary ammonium salt of deep eutectic solvent (DES) is presented, which opens a new access to ester using DES as alkylating agent, solvent, and catalyst. The reaction runs smoothly in DES without any other additives. Substituted cinnamic acids, aromatic acids, and aliphatic acids can be esterified in moderate to good yields. The advantages of this reaction include excellent functional group compatibility and simple reaction procedure.
GRAPHICAL ABSTRACT
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Notes
1Note: In consideration of the decomposition of quaternary ammonium salt in deep eutectic solvent, tertiary amines were put into the reaction and the results were listed in (Entries 5 and 6), the results of showed that tertiary amines were not good alkylating agent of carboxylic acids.