Solvent effect on the relative nucleofugalities of pyridines and phenoxide ions: Broensted-type plots in the pyridinolysis of 2, 4-dinitrophenyl methyl carbonate and 2, 4- …

EA Castro, MT Borquez, PM Parada

Index: Castro, Enrique A.; Borquez, Maria T.; Parada, Paulina M. Journal of Organic Chemistry, 1986 , vol. 51, # 26 p. 5072 - 5077

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Citation Number: 15

Abstract

Curved Brernsted-type plots (log kN vs. pK,) are obtained for the nucleophilic reactions of the title in 44 wt 70 aqueous ethanol, at 25" C, ionic strength 0.2 M (KC1). The curves are described by a semiempirical equation based on the existence of a tetrahedral intermediate (Ti) in the reaction path and a change of the rate-determining step from breakdown to formation of Ti as the pyridine is more basic. The pK, value at the center of curvature (pK2) ...