Long range ¹³C¹H coupling constants IV—methoxy‐, amino‐ and hydroxypyridines

Abstract

Abstract One bond and long range 13 C 1 H coupling constants for some methoxy‐, amino‐ and hydroxypyridines are described. An unambiguous assignment of carbon‐13 resonances is carried out based on the analysis of the fine splitting caused by long range couplings. J values for compounds other than 2‐ and 4‐hydroxy‐pyridines are explainable in terms of the values previouly obtained for cyano‐ and methylpyridines. The hydroxypyridine‐pyridone tautomerism affects 2 J (H α ), i.e. 2 J associated with the α proton. This effect can be used to differentiate pyridones from hydroxypyridines.