Reactions of carbonyl compounds in basic solutions. Part 13. The mechanism of the alkaline hydrolysis of 3-(3-substituted phenoxy)phthalides, -3-methyl-phthalides, -3-phenylphthalides, naphthalides, -3-phenylnaphthalides, and phenanthralides, and of 3-substituted 3-methoxyphthalides
作者:Fredrick Anvia、Keith Bowden、Faiq A. El Kaissi、Victoria Saez
DOI:10.1039/p29900001809
日期:——
effects of substitution on the phenoxy esters have been assessed by means of, the Hammett equation. The results for the methyl esters are related to the steric effect of substituents using the Taft equation. All the pseudo-esters are hydrolysed with rate-determining attack by hydroxide anion at the carbonyl group, followed by rapid ring fission to form the carboxylate anion of the corresponding acid as the
已经测量了在30.0和50.0°C下对3-(3-取代苯氧基)邻苯二甲酸酯,-3-甲基邻苯二甲酸酯,-3-苯基邻苯二甲酸酯,萘二甲酸酯,-3-苯基萘二甲酸酯和邻苯二甲酰胺进行碱水解的速率系数,伪-2-酰基苯甲酸甲酯在70%(v / v)的二恶烷水溶液中处于多个温度下。已经评估了激活的焓和熵。已经通过哈米特方程评估了取代对苯氧基酯的影响。使用Taft方程,甲酯的结果与取代基的空间效应有关。所有的拟酯均被羰基上的氢氧根阴离子水解,以决定速率的方式进行水解,然后迅速发生环裂变,形成相应酸的羧酸根阴离子。在六个系列的苯基假酯的整个范围内都没有显示出反应性-选择性。根据过渡态的结构以及影响反应性的空间,立体化学和极性因素讨论了这些结果。