Kinetics and mechanism of acid-catalyzed hydrolysis of the diazo functional group of diazophenylacetamide

The acid-catalyzed hydrolysis of diazophenylacetamide giving mandelamide as product was found to occur with a normal (kH/kD>1) hydronium ion isotope effect and to be subject to general acid rather than specific hydronium ion catalysis. This shows that the reaction occurs by rate-determining hydron transfer from the catalyzing acid to the diazo carbon atom of the substrate, followed by rapid displacement of the diazo group by water. Comparison of the rate of this reaction with those of the same process for other diazophenylacetic acid functional derivatives, PhCN2COX, reveals that the reactivity of these substrates is controlled by the electron-releasing resonance ability of the group X. Copyright © 2003 John Wiley & Sons, Ltd.