The rate constants of the title reactions have been measured at various amine concentrations. The second-order kinetic constant for the amino substitution increases in a hyperbolic way as a function of the nucleophile concentration. The k3Am/k-1 ratio for each catalysed system is not a monotonic function of the X substituent. This result has been rationalized in the framework of the SB-GA (Specific Base-General Acid) mechanism of base catalysis.
本文研究了在不同胺浓度下的标题反应速率常数。氨基取代的二阶动力学常数随着亲核物浓度的增加而呈双曲线增长。每个催化系统的k3Am/k-1比值不是X取代基的单调函数。这个结果在碱催化的SB-GA(特定碱-一般酸)机制框架内得到了解释。