Intramolecular Catalysis of Dialkyl ω-Aminoalkylphosphonate Hydrolysis

Abstract

The influence that intramolecular catalysis of hydrolysis of O-alkyl S-[2-( dialkylamino )ethyl] alkylphosphonothioates by amino groups may have on the product distribution of the reaction is investigated by study of a series of model compounds. The hydrolysis of diethyl [ω-( ethylamino )alkyl] phosphonates and diethyl [ω-( diethylamino )alkyl] phosphonates has been investigated at 75°C over the pH range 8.21-11.45. Contributions to hydrolysis of the ethoxy groups by intramolecular catalysis by the amino groups have been identified for [2-(amino)ethyl]- and [3-(amino) propyl ]- phosphonates. Secondary and tertiary amino groups assist hydrolysis through general base catalysis. An additional contribution to hydrolysis of the secondary amino compounds by intramolecular nucleophilic catalysis is also observed.