Scheme 3. Study of the kinetics of the reaction between sulfenic acid 15 and dimedone 1. (A) Reaction pathway showing the adduct formation as a result of the reaction of sulfenic acid 15 and dimedone 1. (B) Pseudo 1st order rate constants at varying concentration of 1 (0.5 –2.5 mM), while keeping concentration of 14 fixed (100 μM) were obtained. k obs at different dimedone concentrations were plotted to give the 2nd order rate constant value of 11.8 M–1 s–1. (C) pH dependence of the reaction of dimedone 1 with sulfenic acid 15 was studied. Pseudo 1st order k obs thus obtained were plotted against pH to obtain a sigmoid plot.
