A Kinetic Analysis of the Iodination of Pyruvic Acid and Pyruvate Esters

In the present work the relative rates of iodination of pyruvic acid and ethyl and methyl pyruvate have been compared at 25.0° C. These studies allow the determination of the respective free energies of activation for these processes. Measurements have also been carried out at various temperatures to determine the enthalpies and entropies of activation for the spontaneous and base catalysed iodinations of these pyruvate systems. The present thesis also includes a comparison of the solvent deuterium isotope effects associated with the spontaneous rate of iodination of pyruvic acid and the alkyl pyruvates. Also, the catalytic rate coefficients associated with the basic components of various buffers have been determined for the iodination of methyl pyruvate. These values together with the spontaneous rate of iodination allow the determination of the Brønsted coefficient, S, associated with this process. From these kinetic results, we hope to delineate the mechanism of catalysis for the enolization of pyruvate systems: by distinguishing between intra- and intermolecular catalysed pathways and by accessing the relative importance of carbon-hydrogen bond breaking, and oxygen-hydrogen bond making in the transition states of these enolization processes