Based on the analyses of 1D and 2D NMR spectra techniques, such as H–H COSY, HSQC, and HMBC of 3-[L-threo-2,3,4-trihydroxy-1-(phenylhydrazono)butyl]- quinoxalin-2(1H)-one in dimethyl sulfoxide solution, it was concluded that this compound exists as a mixture of two isomeric Z- and E- forms I and II rather than the hydrazine imine and diazeny enamine V tautomers reported earlier. The NMR signals assignment was supported using density functional theory.

中文翻译：

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3-[L-threo-2,3,4-tri-hydroxy-1-(phenyl-hydrazono)butyl] quinoxalin-2(1H)-one 在二甲亚砜溶液中的异构混合物的结构解析：实验和理论学习

基于 1D 和 2D NMR 光谱技术的分析，例如 3-[L-threo-2,3,4-trihydroxy-1-(phenylhydrazono)butyl]-quinoxalin-2 的 H-H COSY、HSQC 和 HMBC (1H)-一种在二甲亚砜溶液中，得出的结论是该化合物以两种异构体 Z-和 E-形式 I 和 II 的混合物存在，而不是早先报道的肼亚胺和二氮烯胺 V 互变异构体。使用密度泛函理论支持 NMR 信号分配。