Decarboxylation of 6-nitrobenzisoxazole-3-carboxylate ion in dichloromethane: The effects of surfactant structure

The spontaneous decarboxylation of the 6-nitrobenzisoxazole-3-carboxylate ion, 1, in dichloromethane is catalyzed by amine oxide surfactants, C14H29N+ R2O-, R = Me, n-Pr, and less strongly by betaine sulfonate surfactants. The amine oxides are sufficiently basic in the solvent to deprotonate the carboxylic acid. Solutions of the amine oxides tolerate water which, as with cationic surfactants, sharply inhibits reaction, but solutions of C14H29N+ R2SO3-, R = Me, n-Pr, will not tolerate water. The water inhibitions are probably due to formation of 'water-pool' reverse micelles which are catalytically less effective than small surfactant clusters.