Dicyclohexylcarbodiimide (DCC) has been used in the past as a condensing agent in ester synthesis. Yields of ester using this route have been reported as unsatisfactory due to the formation of the by-product, an N-acylurea compound. A catalytic amount of p-toluenesulfonic acid in addition to DCC was used for the synthesis of naphthyl esters. Several other attempts to achieve esterification were also tried but were found to be unsuccessful. One method involved the in situ generation of the carboxylate anion in DMF by the use of a base followed by subsequent alkylation with an alkyl halide. Another method attempted for esterification was acylation of a carboxylic acid. The preferred method for the synthesis of a naphthyl ester was that using DCC as the condensing agent with catalytic amounts of a strong acid.
1,3-dicyclohexylcarbodiimide - esterification -
p-toluenesulfonic acid - naphthyl ester - dicyclohexyl urea
