2-Pyridone and derivatives: gas-phase acidity, proton affinity, tautomer preference, and leaving group ability

The fundamental properties of the parent and substituted 2-pyridones (2-pyridone, 3-chloro-2-pyridone, and 3-formyl-2-pyridone) have been examined in the gas phase using computational and experimental mass spectrometry methods. Newly measured acidities and proton affinities are reported and used to ascertain tautomer preference. These particular substrates (as well as additional 3-substituted pyridones) were chosen in order to examine the correlation between leaving group ability and acidity for moieties that allow resonance delocalization versus those that do not, which is discussed herein.