不对称β-二酮分子内氢键及酮-烯醇互变异构的~1H NMR研究

Study on Intramolecular Hydrogen-Bonding and Keto-Enol Tautomerism of Some Asymmetrical β-Diketones by 1H NMR

研究了一系列二芳甲酰甲烷化合物在不同溶剂中的分子内氢键及酮-烯醇互变异构平衡。δ_(OH)和lgK与取代基常数(σ)之间均有良好的线性关系存在。+I和+R取代基使分子内氢键增强,而使烯醇式含量降低。

The intramolecular hydrogen-bonding and keto-enol tautomerism of a series of 1-aryl-3-tolyl-1,3-propanediones were studied by 1H NMR. Both δOH and lgK(K=[enol]/[keto]) can be correlated with substituent constants satisfactorily. +1 and +R substituents enhance the hydrogenbond-ing and decrease the content of enol form.