Carboxylic acids are ubiquitously present in natural products,such as rosin acid,citric acid,succinic acid,succinic acid,acetic acid,and benzoic acid.Carboxylic acid group is one of the most attractive functional groups in organic synthesis.Benzoic acid is an important aromatic acid among natural carboxylic acids,which naturally exists in various plants and foods.Due to its high biological activity and significant application value,it has garnered widespread attention and is commonly employed in various fields including fragrances,pesticides,dyes,pharmaceuticals,and food.17 benzyl benzoate compounds were synthesized by the electrochemical method from benzoic acid and aryl propionic acid.The altered benzoic acid contains groups,including benzoate 1-phenyl ethyl ester(3a),benzyl benzoate(3b-3e)with different substituents in para or ortho position and 1-phenylethylthiophene-2-carboxylate(3f).The corresponding compounds of aryl propionic acid were synthesized,including benzyl benzoate(3g-3m),phenyl benzyl benzoate(3n),benzoate 1-phenylpropyl benzoate(3o),1-(4-isobutylphenyl)ethyl benzoate derived from the drug molecule ibuprofen(3p),9H-fluorene-9-phenyl benzoate(3q).The structure of the product was confirmed by 1H NMR.Using 2-phenylpropionic acid and benzoic acid as model substrates,the impact of various types of electrolytes on the yield was consecutively examined,as electrolytes play a direct role in determining the conductivity of the entire reaction system.Furthermore,this study delved into how varying dosages of the same electrolyte affect the yield.Electrode materials,serving as both positive and negative electrodes,were also identified as a crucial factor that influences reaction effectiveness.Additionally,this study considered the influence of different types of bases,including inorganic and organic alkalis,on the yield.Organic alkalis notably exhibited significantly better solubility compared to inorganic alkalis,and the quantity of base used also significantly impacts the yield.Furthermore,this study explored the effects of various solvents and solvent mixtures on the yield,noting that these solvents differed in their conductivity properties.Then,the impact of varying current and voltage levels on the yield was also investigated.Finally,the reaction was carried out under the condition of a constant current of 10 mA,with dichloromethane(DCM,0.05 mol/L)as the solvent.In the presence of tetrabutylammonium perchlorate(nBu4 NClO4,0.9 mmol)and 2,4,6-trimethylpyridine(0.45 mmol),the reaction was carried out for 6 h.After the reaction was completed,the product was separated by column chromatography,and the yield of product 3a was calculated to be 99％.A variety of benzyl benzoate compounds using benzoic acid or phenylpropionic acid as raw material could be tolerated under the optimized reaction conditions and the yield of 3b-3q was between 56％and 94％.
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