Heterocyclic β-enamino esters 43—easy13C NMR distinction between aryl-substituted dimroth isomers of the 1,2,3-triazole series
作者:H. Wamhoff、J. Bohlen、S. Y. Yang
DOI:10.1002/mrc.1260240914
日期:1986.9
5-Amino-1-aryl-1,2,3-triazoles and 5-anilino-1,2,3-triazoles can be easily distinguished by their 13C NMR spectra. Thus, C-4 and C-5 of some studied 5-anilino isomers are deshielded by 2–5 ppm in comparison with the corresponding 5-amino-1-aryl isomers. From the 13C NMR signals of the aryl carbons in the same 5-anilino isomers, C-6 is shifted downfield (ca 9 ppm; –I effect), whereas C-7 and C-9 are shifted upfield (ca 7 and 10 ppm, respectively; +M effect). This allows a fast and easy assignment of both Dimroth isomers.
5- 氨基-1-芳基-1,2,3-三唑和 5- 苯胺基-1,2,3-三唑的 13C NMR 光谱很容易区分。因此,与相应的 5-氨基-1-芳基异构体相比,所研究的一些 5-苯胺基异构体的 C-4 和 C-5 被去屏蔽 2-5 ppm。从相同 5-苯胺异构体中芳基碳的 13C NMR 信号来看,C-6 被下移(约 9 ppm;-I 效应),而 C-7 和 C-9 被上移(分别约 7 和 10 ppm;+M 效应)。这使得两种二聚体异构体的分配变得简单快捷。