Intramolecular general base catalysis in the hydrolysis of 3-dimethylaminopropionates

Abstract

The hydrolysis of p-nitrophenyl 2-dimethylaminobenzoate, and of a series of substituted-phenyl 3-dialkylaminopropionates, is subject to intramolecular catalysis by the dialkylamino group. A general base catalysis mechanism is indicated. General base catalysis of hydrolysis by tertiary nitrogen is characterised by solvent deuterium isotope effects which fall with increasing basicity of the general base, to as low as k_H/k_D= 1.4. These low values are associated with a significant increase in the sensitivity of the reaction to the basicity of the leaving group, compared with similar reactions catalysed by oxyanions.