Aminolysis of Methyl Y-Aryl Phosphorochloridothionates

초록

Nucleophilic substitution at phosphorus has been considered to proceed through either stepwise through a penta coordinate intermediate or concertedly through a single TS. It has great interest to study for P=S system. A few works are reported for P=S system. To this scientific viewpoint we have studied the kinetics and mechanism of aminolysis of methyl Y-aryl phosphorochloridothionates with anilines and pyridines at 55℃ and 35℃ respectively in acetonitrile. The mechanistic change has been observed for the reactions of methyl Y-aryl phosphorochloridothionates with anilines and pyridines. This conclusion has been drawn based on biphasic Hammett and BrÖnsted plots. As a result negative as well as positive cross interaction constant (rXY) have obtained which are indicative of mechanistic change. The rates are faster in case of pyridines.