The one- and two-dimensional ¹⁵N NMR spectra of (E)- and (Z)-2-(2-(2-hydroxy-4-nitrophenyl)hydrazono)-1-phenylbutane-1,3-diones (1) were measured and analysed and ¹⁵N chemical shifts and ¹J (¹⁵N, ¹H) coupling constants were used for characterization of these two compounds from the viewpoint of azo-hydrazo tautomerism. Both compounds exist completely in appropriate hydrazo forms in dimethyl sulfoxide.

Advantages of ¹⁵N NMR spectroscopy application in determination of acidic proton positions and azo-hydrazo content determination are discussed. We would like to propose the application of ¹⁵N NMR data measured at the natural abundance level of ¹⁵N as the “first glance” and strongest evidence method for the existence of hydrazo form in azo dyes and for differentiation of E- and Z-isomers around C=N_β double bond.

（E）-和（Z）-2-（2-（2-（2-羟基-4-硝基苯基）肼基）-1-苯基丁烷-1,3-二酮的一维和二维¹⁵ N NMR光谱（1）从偶氮-偶氮互变异构现象的角度，对这些化合物进行了测量和分析，并使用¹⁵ N化学位移和¹ J（¹⁵ N，¹ H）耦合常数表征了这两种化合物。两种化合物都以适当的oxide形式完全存在于二甲基亚砜中。

的优点¹⁵ ÑNMR光谱中测定酸性质子的位置和偶氮肼含量测定的应用进行了讨论。我们想提出的应用^15个以天然丰度水平测量ÑNMR数据¹⁵ N作为“第一一瞥”和有力的证据方法用于偶氮染料和分化亚肼基形式存在ë -和ž -异构体C ＝_Nβ双键附近。