Fourteen model phenyl esters of 2-substituted benzoic acids were synthesised. Structures and purity of model compounds were confirmed by 1H and 13C NMR spectroscopy, as well as by HPLC and elemental analysis. Kinetics of base-catalysed hydrolysis of model phenyl esters occurring by the BAc2 mechanism were measured by UV spectrophotometry in 50% (v/v) aqueous dimethyl sulfoxide solutions at 25 °C under pseudo-first-order reaction conditions (c(NaOH) = 0.001-1.0 mol l-1). Linear relation between J-E and log kobs with the slope close to unity was found for all model compounds. Neither one-parameter nor multiparameter Hammett-type description of variability of experimental data obtained for phenyl esters of 2-substituted benzoic acids was found. Two groups (conjugating and non-conjugating) were created by division of ortho-substituents in ortho-position using the AISE theory, based on their interaction with the reaction centre.
2-取代
苯甲酸的十四种模型苯基酯已合成。通过
1H和
13C核磁共振波谱、高效
液相色谱和元素分析确认了模型化合物的结构和纯度。在25°C下,通过UV分光光度法在50%(体积分数)
水溶性
二甲基亚砜溶液中测量了模型苯基酯的碱催化
水解动力学,反应条件为伪一级反应条件(
c(NaOH) = 0.001-1.0 mol l
-1)。发现所有模型化合物的
J-E与log
kobs之间存在线性关系,斜率接近于单位。未发现适用于2-取代
苯甲酸苯基酯实验数据变异性的单参数或多参数Hammett类型描述。通过使用AI
SE理论,根据它们与反应中心的相互作用,将
邻位取代基分为两组(共轭和非共轭)。