Kinetics and Mechanism of The Pyridinolysis of O,O-Dimethyl S-Aryl Phosphorothioate in Dimethyl Sulfoxide

초록

The mechanistic interpretation with its statistical database of physical behavior of organo-phosphorus compounds are appearing as an interesting materials for bioactive and biosencing materials recently in physical organic chemistry. Usually the Hammett and Brönsted plots are indicated the mechanistic criteria during the change in X or Z-substituents variation of nucleophiles or substrate respectively. The nonlinear Hammett and Brönsted plots are the indication of mechanistic change during the course of reactions. The Deuterium Kinetic Isotope Effect (DKIE) is the strong tool for mechanistic interpretation and interpreted primary deuterium kinetic Isotope Effect confers the H-bond effect at the TS. The respective activation parameters and obtained cross-interaction constants (ρXZ = ‒0.15 and ‒0.35) with large positive ρX (For 4-NH2 – H, 1.51 – 1.73 and For H – 4Ac, 0.959 – 1.10), ρZ (For 4-MeO – 4-Cl, 1.05 – 1.35) and βX (For 4-NH2 – H, 0.250 – 0.288 and For H – 4Ac, 0.190 – 0.219) are the main basic information for interpreting mechanism. Where, we are especially endeavored to introduce the frontal and backward attack of nucleophiles through the usual SN1 or SN2 processes. In the present work, we intended to speculate and provoke the concerted SN2 mechanism with the early TS from the Cross Interaction Constants, Hammett and Brönsted correlations in the course of reactions mentioned above.