作者:P. Barraclough、J. C. Lindon、M. S. Nobbs、J. M. Williams
DOI:10.1002/mrc.1260271016
日期:1989.10
A detailed analysis of the 13C NMR spectra of the 1-N- and 3-N-methyl derivatives of 1H-2-(2,4-dimethoxyphenyl)imidazo[4,5-c]pyridine, utilizing long-range couplings and 2D 1H13C correlation experiments, has led to an unambiguous assignment of all carbons. Comparison of these definitive assignments of C-3a and C-7a, in particular, with those of the tautomers of 1H-2-(2,4-dimethoxyphenyl)imidazo[4,5-c]pyridine has permitted confirmation of the predominance of the 1H-tautomer for the latter. In addition, previous conflicting assignments for 1H-imidazo[4,5-c]pyridine and its 3-N-methyl derivative are now resolved. Revision of these assignments leads to the conclusion that the 1H-tautomer of 1H-imidazo[4,5-c]pyridine is predominant.
通过利用远程耦合和二维1H-13C相关实验对1H-2-(2,4-二甲氧基苯基)咪唑并[4,5-c]吡啶的1-N-和3-N-甲基衍生物的13C NMR谱进行详细分析,已明确确定了所有碳原子的归属。特别是,将C-3a和C-7a的确切归属与1H-2-(2,4-二甲氧基苯基)咪唑并[4,5-c]吡啶的互变异构体的归属进行比较,证实了后者的1H型互变异构体占主导地位。此外,之前对于1H-咪唑并[4,5-c]吡啶及其3-N-甲基衍生物的归属存在冲突,现在得到了解决。重新修订这些归属得出结论:1H-咪唑并[4,5-c]吡啶的1H型互变异构体占主导地位。