苯甲酰-1,3-环己二酮类化合物互变异构的理论计算

对苯甲酰-1,3-环己二酮的各异构体进行了HF/6-31G＊水平的几何优化,然后对能量低的三酮式和2个顺式烯醇式异构体进行了更广泛的计算,探讨了计算方法、基组大小对异构体相对稳定性的影响。在此基础上,对该类化合物的互变异构化平衡常数、能垒进行了计算,在平衡常数的计算中充分考虑了溶剂的影响并结合实验结果进行了分析。最后,对有代表性的苯环2-位取代衍生物进行了计算,发现互变异构自由能与其HPPD酶抑制活性间存在着较好的相关关系。

Studies on the Tautomerism of Benzoylcyclohexane-1,3-dione and Its Derivatives by Ab Initio Calculation

Geometry optimizations were performed at different levels for the most stable triketone tautomer and cis-endocyclic double bond enol tautomers of benzoylcyclohexanedione. The effect of the calculation method and the size of the basis set on the relative stability of the tautomers were investigated therein. We calculated the equilibrium constants and the energy barrier of the benzoylcyclohexane-l,3-dione to study the tautomerization. The solvent effect was taken into account when calculating the equilibrium constants and the results were analyzed by comparing with the experimental results. Finally, the calculations were performed on several typical 2-substituting benzoylcyclohexane-l,3-dione derivatives. It appears that the tautomerism free energy and their HPPD inhibitive activity are correlated to some extent.