Hammett equation pyridine 1-oxides

Chapman and co-workers have investigated the nucleophilic displacement of chlorine in various chloronitropyridines by three pyridines. In each of these series of three compounds, an excellent correlation is observed, but, again, longer series would be extremely desirable. Similarly, the nucleophilic attack of a series of four pyridines on propylene oxide follows the Hammett equation with high pre-... 

While it has been known for some time that pyridine-1-oxides are protonated on oxygen (Gardner and Katritzky, 1957), amino-pyridine-1-oxides have attracted more attention recently. Using the Hammett equation, it was concluded that the cation of 3-amino-pyridine-1-oxide was an equilibrium mixture of O- and N-protonated forms in the ratio 8 1 (Jaffe, 1965), A similar conclusion was reached for 3-dimethylaminopyridine-l-oxide (Forsythe et al.,... 

The Hammett equation has been applied to ipKa values for the excited states of pyridines and pyridine l-oxides soa... 

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