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本文研究了二十六种β-双酮系化合物的核磁共振谱。分析讨论了主要基团的化学位移。还讨论了中两个甲基在化学上不等性是由于结构呈晾式,而不是呈偶氮式。从3-位质子的化学位移分析表明,R~1、R~2和R~3的电负性是影响3-位质子化学位移的主要原因,空间效应则是很小的。我们认为R~1、R~2和R~3的电负性和空间效应对烯醇化都有显著作用。最后,讨论了实验结果与Shapet’ko计算结果的一致性和烯醇化的方向性,并用Shapet’ko的结果推算出一些化合物中R~3对δ_(OH)的贡献。
In this paper, the NMR spectra of twenty-six β-diketone compounds were studied. The chemical shifts of the major groups are discussed and discussed. It is also discussed that the chemical inequality of the two methyl groups is due to the structure being air-dried rather than azo-type. The chemical shifts of 3-position protons show that the electronegativities of R ~ 1, R ~ 2 and R ~ 3 are the main reasons that affect the 3-position proton chemical shift and the space effect is very small. We think that the electronegativity and steric effects of R ~ 1, R ~ 2 and R ~ 3 have a significant effect on enolase. Finally, the agreement between experimental results and Shapet’ko calculations and the enolase orientation are discussed. The contribution of R ~ 3 to δ_ (OH) in some compounds is deduced from the results of Shapet’ko.