This has been confirmed by X-ray crystallography which shows that the hydrogen in solid state is closer to the nitrogen than to the oxygen (because of the low electron density at the hydrogen the exact positioning is difficult), and IR-spectroscopy, which shows that the C=O longitudinal frequency is present whilst the O-H frequencies are absent.

In the solid state the hydrogen is located closer to the nitrogen so it could be considered to be right to call the colourless crystals in the flask 2-pyridone.

[11][12][13][14][15][16][17][18][19][20] (NMR-spectroscopy is a slow method, high resolution IR-spectroscopy in solvent is difficult, the broad absorption in UV-spectroscopy makes it hard to discriminate 3 and more very similar molecules).

For example, to calculation of the energy difference of the two tautomers in a non-polar solution will lead to a wrong result if a large quantity of the substance is on the side of the dimer in an equilibrium.

The direct tautomerisation is not energetically favoured, but a dimerisation followed by a double proton transfer and dissociation of the dimer is a self catalytic path from one tautomer to the other.

This pyridine-N-oxide undergoes a rearrangement reaction to 2-pyridone in acetic anhydride:[21][22][23] In the Guareschi-Thorpe condensation cyanoacetamide reacts with a 1,3-diketone to a 2-pyridone.

2-Pyridone has a large effect on the reaction from activated esters with amines in nonpolar solvent, which is attributed to its tautomerisation and utility as a ditopic receptor.

[20] Organisms capable of growth on 2-pyridone as a sole source of carbon, nitrogen, and energy have been isolated by a number of researchers.

2-Pyridone degradation is commonly initiated by mono-oxygenase attack, resulting in a diol, such as 2,5-dihydroxypyridine, which is metabolized via the maleamate pathway.

Fission of the ring proceeds via action of 2,5-dihydroxypyridine monooxygenase, which is also involved in metabolism of nicotinic acid via the maleamate pathway.