SELECTIVE MONOMETHYL ESTERIFICATION OF DICARBOXYLIC ACIDS BY USE OF MONOCARBOXYLATE CHEMISORPTION ON ALUMINA.

Article abstract of DOI:10.1021/ja00291a042

The application of alumina as a solid support affords a new procedure for selective reactions. Although it is difficult to obtain monoesters in the esterification of dicarboxylic acids by conventional methods, dicarboxylic acids adsorbed on alumina selectively form the monoesters. Terephthalic acid (1), isophthalic acid, cis- and trans-1,4-cyclohexanedicarboxylic acids, and aliphatic dicarboxylic acids give the corresponding monomethyl esters quantitatively with diazomethane. On the basis of these results, the authors suggest that dicarboxylic acids are adsorbed on alumina through one of their carboxyl groups, and the carboxyl group not adsorbed on the alumina is esterified selectively. Selective monomethyl esterification of phthalic acid is not successful on alumina, probably as a consequence of the close proximity of the two carboxyl groups and the forced orientation of the second group when one is adsorbed.