Recent Developments in Amide Synthesis: Direct Amidation of Carboxylic Acids and Transamidation Reactions

The synthesis of amides is of huge importance in a wide variety of industrial and academic fields and is of particular significance in the synthesis of pharmaceuticals. Many of the well established methods for amide synthesis involve reagents that are difficult to handle and lead to the generation of large quantities of waste products. As a consequence, there has been a considerable amount of interest in the development of new approaches to amide synthesis. Over the past few years a wide range of new reagents and catalysts for direct amidation of carboxylic acids have been reported. In addition, the interconversion of amide derivatives through transamidation is emerging as a potential alternative strategy for accessing certain amides. This microreview covers recent developments in the direct amidation of carboxylic acids and the interconversion of amides through transamidation. The advantages and disadvantages of the various methods are discussed, as well as the possible mechanisms of the reactions.