An improved method for the catalytic preparation of t-butyl esters of carboxylic and fatty acids

Esterification of various acids such as fatty acids, simple carboxylic acids, and N^α blocked amino acids by t-butanol in very high yield is described. The one-pot esterification is achieved by dicyclohexylcarbodiimide (DCC) and catalyzed by dimethylaminopyridine (DMAP). This procedure overcomes the excessive formation of the undesired side product, N-acyl urea obtained normally when a DCC/DMAP-mediated esterification of fatty acids is attempted. The procedure is based on studies of reaction rate and product distribution under various reaction conditions. A suggested mechanism for the esterification of fatty acids is presented.