On the question of stepwise vs. concerted cleavage of RNA models promoted by a synthetic dinuclear Zn(<scp>ii</scp>) complex in methanol: implementation of a noncleavable phosphonate probe
作者:David R. Edwards、Wing-Yin Tsang、Alexei A. Neverov、R. Stan Brown
DOI:10.1039/b918310h
日期:——
constant of the conjugate acid of the leaving group in methanol) was fitted to a linear regression of log kcatmax = (−0.80 ± 0.07)sspKa + (10.2 ± 1.0) which includes the datum for 6a. The datum for 6b, which reacts ∼70–fold slower, falls significantly below the linear correlation. The data provide additional evidence consistent with a concerted cyclization of RNA models 1a–k promoted by 4.
为了解决由双核Zn(II)络合物(4)在s s pH 9.8和25°C促进的2-羟丙基芳基和烷基RNA模型(1a-k)环化的协调反应和逐步反应机制的问题,不可裂解的O-羟丙基苯基膦酸酯类似物6a和6b在甲醇。这些膦酸酯未在研究中进行异构化,唯一可观察到的甲醇分解反应是释放出1,2-丙二醇并形成邻甲基苯基膦酸酯。用于甲醇分解通过促进所观察到的一级速率常数4是ķ OBS 6A =(1.47±0.09)×10 -4小号-1和ķ OBS 6B =(2.08±0.09)×10 -6小号-1,分别。在增加[ 4 ]的条件下,分析了一系列邻芳基苯基膦酸酯(8a–f)的甲醇分解速率,以提供结合常数K b和催化速率常数k cat max。,用于8 : 4 Michaelis配合物的单分子分解。log(k cat max)对s s p K a苯酚(布环烷基中离去基团的共轭酸的酸度常数)的布朗斯台德图。甲醇)拟合为log