72046-55-0Relevant academic research and scientific papers
Kinetics and Mechanism of the Hydrolysis of Anilide Acetals
McClelland, Robert A.,Patel, Geeta
, p. 6908 - 6911 (2007/10/02)
A kinetic study of the hydrolysis of anilide acetals ArC(OMe)2NMeAr' is reported.At high pH (>10) a pH independent C-O cleavage reaction is observed producing methanol and benzimidatonium ion; the latter is further hydrolyzed to amide and ester products.Substituent and solvent effects support a simple ionizaiton mechanism with a transition state near the ion.At pH + catalysis attributable to pre-equilibrium protonation followed by rate-determining cleavage.Estimation of the pKa of the protonated anilide acetal (-1) provides an estimate of its rate of C-N cleavage (ca.108 s-1) which is near the diffusion limit.At pH 7 there is a change in the rate-determining step in product formation in this C-N cleavage reaction, and what is observed kinetically is the decomposition of the hemiorthoester ArC(OMe)2OH, the product of hydration of the dialkoxy carbocation.The principal piece of evidence for the changeover is the observation that the rate constants in acid solution are independent of the aniline moiety of the anilide acetal.
