Determination of hydration equilibrium constants and p K a values of 4‐piperidones in buffered water solutions

1 H and 13 C chemical shift parameters are given for 4‐piperidones and their derivatives in buffered aqueous solution. The 13 C shift increments of methyl substituents on the nitrogen atom are discussed. The pH‐shift dependence is studied in detail and p K a values are given for ketone forms and hydration products. The hydration equilibria are measured as a function of pH and temperature.