atom of the substrate. Analysis of the rate profile for the reaction provides an estimate of the acidity constant of phenyldiazoacetic acid, pKa = 3·70, which is apparently the first determination of the acid strength of an α-diazocarboxylic acid. Comparison of this result with the pKa of phenylacetic acid shows the diazo group to have a mild (4×) acid-strengthening effect, whose modest magnitude is
在25°C的
水溶液中,在整个酸度范围p C = 1-13范围内,测定了酸催化的苯基
重氮乙酸水解速率。发现该反应通过基材的非电离形式和非电离形式发生,电离形式的反应速度提高了650倍。在法向(k H / k D > 1)和常规酸分析的发生表明
水解是通过速率确定质子转移到底物的重氮碳原子上而发生的。反应速率曲线的分析提供了对苯
重氮乙酸的酸度常数p K a的估计。= 3·70,这显然是α-重氮
羧酸的酸强度的首次测定。该结果与
苯乙酸的p K a的比较表明,重氮基团具有温和的(4x)酸增强作用,其适度的幅度归因于相反的共振和极性作用。