General-Base Catalysis in the Reaction of Water with Activated Aromatic Substrates. The Hydrolysis of 3-Methyl-1-picrylimidazolium Ion

Article abstract of DOI:10.1021/jo00159a018

The rate of hydrolysis of 3-methyl-1-picrylimidazolium ion was investigated between pH 1.7 and 9.3 in the presence of several buffer bases at various concentrations.The reaction is strongly catalyzed by oxygen bases.The catalytic constants including water and OH^- are spread over a range of ten powers of ten and show a good Broensted correlation with β=0.62.The kinetic solvent isotopic effect for the water-, acetate-, and OH^--catalyzed reactions are 2, 0.86, and 0.84, respectively.The mechanism of catalysis is discussed, and it is concluded that it represents concerted addition of water to the aromatic ring.