Reexamination of the Kirkwood–Westheimer theory of electrostatic effects. V. Effect of charged substituents on the rates of alkaline hydrolysis of substituted strychnines

Abstract

The rates of hydrolysis in aqueous sodium hydroxide of the alkaloid strychnine and seven of its derivatives have been determined at 50 and 75 °C. The kinetic data indicate that all the compounds, except strychninesulfoni acid-I, hydrolyze by competing second- and third-order mechanisms, involving one and two hydroxide ions, respectively; strychninesulfonic acid-I hydrolyzes by the second-order mechanism only. The quantitative effect of positively charged groups in enhancing, and negatively charged groups in depressing, the rates of hydrolysis is in rough agreement with calculations using Kirkwood–Westheimer theory. Keywords: Kirkwood–Westheimer theory; strychnine derivatives, hydrolysis of; lactams, hydrolysis of; electrostatic effects on rates of alkaline hydrolysis; alkaloids, reactions of.