H1 and C13 NMR chemical shifts for neutral (3-hydroxypyridine and 3-methoxypyridine) and zwitterionic (N-ethyl-3-oxypyridinium betaine and 3-pyridone) molecules were calculated by GIAO/B3LYP/6-31G(d,p) and IGLO/deMon/NMR approaches. Linear correlations between the calculated and experimental 1H and 13C NMR chemical shifts for 3-hydroxypyridine, 3-methoxypyridine, and N-ethyl-3-oxypyridinium betaine suggest that the 3-hydroxy tautomer is dominant in DMSO-d6. The lack of such a correlation for 3-pyridone indicates an absence of this species in DMSO-d6 solution.
Jul 30, 2014
May 26, 2014