A Facile Synthesis of Racemic 4-Ethyl Fatty Acids

Abstract

The synthesis of racemic 4-ethyl fatty acids is reported. A Grignard reagent was first prepared by 3-chloroalkane reacting with magnesium and then 4-ethyl fatty acid methyl esters were synthesised by coupling the Grignard reagent with methyl 3-bromopropionate in the presence of the catalyst Li2CuCl4. The 4-ethyl fatty acid methyl esters were saponified and then acidified to give the 4-ethyl fatty acids. The syntheses of 4-ethylhexanoic acid, 4-ethylheptanoic acid, 4-ethyloctanoic acid, 4-ethylnonaoic acid and 4-ethyl decanoic acid are described. The structures of the 4-ethyl fatty acid methyl esters and 4-ethyl fatty acids were confirmed by 1H NMR, 13C NMR and HRMS.