Kinetics and mechanisms of the reactions of S-methyl chlorothioformate with pyridines and secondary alicyclic amines
作者:Enrique A. Castro、Margarita Aliaga、Marcela Gazitúa、José G. Santos
DOI:10.1016/j.tet.2006.03.013
日期:2006.5
Brønsted-type plot, in agreement with a stepwise mechanism and a change in the rate-limiting step, from formation of a zwitterionic tetrahedral intermediate (T±) at high pKa to its breakdown at low pKa. The reaction of the same substrate with secondary alicyclic amines shows a linear Brønsted-type plot of slope 0.23, which is in accordance with a stepwise mechanism where formation of T± is the rate-determining
S-甲基氯硫代甲酸甲酯的吡啶解反应显示了一个双相布朗斯台德型图,与逐步机理和限速步骤的变化相一致,从在高p K a的两性离子四面体中间体(T ±)形成到其分解在低p K a时。相同底物与脂环族仲胺的反应显示出斜率0.23的线性布朗斯台德图,这符合逐步机理,其中T ±的形成是确定整个p K a范围的速率决定步骤。