Kinetics of reaction of p-nitrophenyl methyl carbonate with nucleophiles in aqueous solution, and the relative ease of acetyl and methoxycarbonyl transfer reactions

Abstract

The rate constants for reaction of eight nitrogen and four oxygen bases with p-nitrophenyl methyl carbonate in water at 25 °C have been measured, and are closely similar to published values for p-nitrophenyl acetate. General acid catalysis is not observed in the methoxyaminolysis of the carbonate, unlike the acetate. Specific salt effects are shown to preclude conclusions regarding the extent of general base catalysis in these reactions. The rate constant for reactions of propylamine with the 1-methoxycarbonyl-4-methylpyridinium ion has also been measured, and is compared with the published value for the 1-acetyl compound.