51103-98-1Relevant articles and documents
Kinetics and mechanism of the aminolysis of aryl phenyl chlorothiophosphates with anilines
Ul Hoque, Md. Ehtesham,Dey, Shuchismita,Guha, Arun Kanti,Chan, Kyung Kim,Lee, Bon-Su,Hai, Whang Lee
, p. 5493 - 5499 (2008/02/09)
(Chemical Equation Presented) Kinetic studies of the reactions of aryl phenyl chlorothiophosphates (1) and aryl 4-chlorophenyl chlorothiophosphates (2) with substituted anilines in acetonitrile at 55.0°C are reported. The negative values of the cross-interaction constant ρXY (ρXY = -0.22 and -0.50 for 1 and 2, respectively) between substituents in the nucleophile (X) and substrate (Y) indicate that the reactions proceed by concerted SN2 mechanism. The primary kinetic isotope effects (kH/kD = 1.11-1.13 and 1.10-1.46 for 1 and 2, respectively) involving deuterated aniline nucleophiles are obtained. Front- and back-side nucleophilic attack on the substrates is proposed mainly on the basis of the primary kinetic isotope effects. A hydrogen-bonded, four-center-type transition state is suggested for a front-side attack, while the trigonal bipyramidal pentacoordinate transition state is suggested for a back-side attack. The MO theoretical calculations of the model reactions of dimethyl chlorothiophosphate (1′) and dimethyl chlorophosphate (3′) with ammonia are carried out. Considering the specific solvation effect, the front-side nucleophilic attack can occur competitively with the back-side attack in the reaction of 1′.
