The electrochemical reduction of some arylethyl chlorides ArCH(CH 3)Cl (Ar = 4-isobutylphenyl, 3-phenoxyphenyl, 6-methoxy2-naphthyl), which are used as precursors in the electrosynthesis of important anti-inflammatory drugs, has been investigated at Ag and glassy carbon (GC) electrodes in CH3CN and DMF. In both solvents Ag shows a remarkable catalytic effect for the electroreduction of the halides. The Ep values obtained at this electrode are 0.34 – 0.55V more positive than those obtained at GC. The electrocatalytic effect of Ag is further enhanced by the presence of CO2, the observed positive Ep shift increasing up to 0.55 – 0.76V in CO2-saturated solvents. The mechanism of the electrochemical reduction of the halides at both electrodes is discussed. Large scale reduction of ArCH(CH3)Cl at Ag carried out in CO2-saturated solvents at 298.15 and 273.15K led to the formation of ArCH(CH3)CO2H as the principal product. Although satisfactory acid yields were obtained in both cases, better results were obtained at the lower temperature; the acid yields were 61 – 73% and 70 – 81% at 298.15 and 273.15K, respectively.

Electrocatalytic reduction of arylethyl chlorides at silver cathodes in the presence of carbon dioxide: Synthesis of 2-arylpropanoic acids

AHMED ISSE, ABDIRISAK;FERLIN, MARIA GRAZIA;GENNARO, ARMANDO
2005

Abstract

The electrochemical reduction of some arylethyl chlorides ArCH(CH 3)Cl (Ar = 4-isobutylphenyl, 3-phenoxyphenyl, 6-methoxy2-naphthyl), which are used as precursors in the electrosynthesis of important anti-inflammatory drugs, has been investigated at Ag and glassy carbon (GC) electrodes in CH3CN and DMF. In both solvents Ag shows a remarkable catalytic effect for the electroreduction of the halides. The Ep values obtained at this electrode are 0.34 – 0.55V more positive than those obtained at GC. The electrocatalytic effect of Ag is further enhanced by the presence of CO2, the observed positive Ep shift increasing up to 0.55 – 0.76V in CO2-saturated solvents. The mechanism of the electrochemical reduction of the halides at both electrodes is discussed. Large scale reduction of ArCH(CH3)Cl at Ag carried out in CO2-saturated solvents at 298.15 and 273.15K led to the formation of ArCH(CH3)CO2H as the principal product. Although satisfactory acid yields were obtained in both cases, better results were obtained at the lower temperature; the acid yields were 61 – 73% and 70 – 81% at 298.15 and 273.15K, respectively.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2448851
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