Hydrolyses of 2- and 4-Fluoro N-Heterocycles. 4. Proton Inventories of the Hydrolyses of 2-Fluoro-1-methylpyridinium Iodide, 4-Fluoroquinaldine, and 2-Chloro-1-methylpyrimidinium Triflate

Article abstract of DOI:10.1021/jo00050a017

Rate constants for the hydrolyses of 2-fluoro-1-methylpyridinium iodide (3), 4-fluoroquinaldine (4), and 2-chloro-1-methylpyrimidinium triflate (5) in 2 * 10^-3 M aqueous sulfuric acid, in D2O/D2SO4, and in mixed H2O/H2SO4-D2O/D2SO4 media are reported.Significant solvent deuterium kinetic isotope effects are evident, with k_H/k_D = 2.07 for 3, 1.62 for 4, and 2.12 for 5.The results of the proton inventories for the hydrolyses of 3 and 5 are best fit by a form of the Gross-Butler equation for three nearly equivalent sites with fractionation factors of 0.78.The proton inventory of 4 does not yield a unique solution to the Gross-Butler equation, but the results are also consistent with three transition state sites with nearly equal fractionation factors of 0.72-0.78, as well as an additional transition-state site with Φ > 1 and a reactant site with Φ