Aminolysis of Aryl <i>N</i>-Ethyl Thionocarbamates: Cooperative Effects of Atom Pairs O and S on the Reactivity and Mechanism
作者:Hyuck Keun Oh、Ji Young Oh、Dae Dong Sung、Ikchoon Lee
DOI:10.1021/jo050606b
日期:2005.7.1
with benzylamines (XC6H4CH2NH2) in acetonitrile are investigated at 30.0 °C. The rate of ETNC is slower by a factor of ca. 3 than the corresponding aminolysis of aryl N-ethyl thiocarbamate (AETC/EtHN-(CO)-SC6H4Z), which has been interpreted in terms of cooperative effects of atom pairs O and S on the reactivity and mechanism. For concerted processes, these effects predict a rate sequence, −C(S)−S− <
在30.0°C下研究了芳基N-乙基硫代氨基甲酸酯(ETNC / EtHN-C(S)-OC 6 H 4 Z)与苄胺(XC 6 H 4 CH 2 NH 2)的氨解反应。ETNC的速度减慢了大约两倍。与芳基N-乙基硫代氨基甲酸酯的相应氨解反应(AETC / EtHN-(C O)-SC 6 H 4 Z)相比,它的原子分解反应要比图3所示,这是根据原子对O和S对反应性和机理的协同作用来解释的。对于一致的过程,这些效应可预测速率序列-C(S)-S- <-C(S)-O- <-C-(O)-S- <-C-(O)-O-,并且当前结果与此顺序一致。负交叉相互作用常数,ρ XZ = -0.87,的幅度β Ž(= 0.36-0.50)和失败的RSP的是在与该协同机制一致。涉及氘化苄胺的正常动力学同位素效应k H / k D = 1.52-1.78表明存在氢键合的环状过渡态。还讨论了影响该机制的其他因素。