Esterification Catalysis by Pyridinium p-Toluenesulfonate Revisited-Modification with a Lipid Chain for Improved
Wei Wang1, Huimin Liu, Shaoyi Xu
1Department of Chemistry and Biochemistry, Southern Illinois University, 1245 Lincoln Drive, Carbondale, Illinois 62901-4409.
Abstract:
The lipid analogues of pyridinium p-toluenesulfonate (PPTS) were examined for catalyzing the condensation of an equimolar mixture of carboxylic acids and alcohols under mild conditions without removal of water. Although PPTS is a poor catalyst, the introduction of a lipid chain and nitro group significantly improved the activity of PPTS and led to selectivity at suppressing elimination side reactions of alcohols. 2-Oleamido-5-nitro-pyridinium p-toluenesulfonate (6) is a lead catalyst that promoted various esterification reactions with yields up to 99%.
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