A1H and13C nuclear magnetic resonance and X-ray diffraction study of the tautomerism of 2-hydroxy- and 2,3-dihydroxy-pyridine N-oxides. X-Ray molecular structure of 2-hydroxypyridine N-oxide

From a 1H and 13C NMR study, in dimethyl sulphoxide, of twelve 2-hydroxy-, 2,3-dihydroxy-pyridines, 2,3-dihydroxypyridine N-oxides, and their methoxy derivatives it is possible to conclude that both pyridin-2-ones and 1-hydroxypyridine-2-ones exist in solution as 2-oxo tautomers. The molecular structure of 2-hydroxypyridine N-oxide has been determined by X-ray diffraction methods; as in solution, this compound exists in the crystal state as the 1-hydroxypyridin-2-one tautomer.