93115-98-1Relevant academic research and scientific papers
Kinetics and mechanism of the anilinolysis of aryl ethyl isothiocyanophosphates in acetonitrile
Barai, Hasi Rani,Adhikary, Keshab Kumar,Lee, Hai Whang
, p. 1829 - 1834 (2013/07/26)
The nucleophilic substitution reactions of Y-aryl ethyl isothiocyanophosphates with substituted X-anilines and deuterated X-anilines were investigated kinetically in acetonitrile at 75.0 oC. The free energy relationships with X in the nucleophiles exhibited biphasic concave downwards with a break point at X = H. A stepwise mechanism with rate-limiting bond formation for strongly basic anilines and with rate-limiting bond breaking for weakly basic anilines is proposed based on the negative and positive ?XY values, respectively. The deuterium kinetic isotope effects (DKIEs; kH/kD) changed gradually from primary normal with strongly basic anilines, via primary normal and secondary inverse with aniline, to secondary inverse with weakly basic anilines. The primary normal and secondary inverse DKIEs were rationalized by frontside attack involving hydrogen bonded, four-center-type TSf and backside attack involving in-line-type TSb, respectively.
Kinetics and mechanism of the aminolysis of aryl ethyl chloro and chlorothio phosphates with anilines
Hoque, Md. Ehtesham Ul,Dey, Nilay Kumar,Kim, Chan Kyung,Lee, Bon-Su,Lee, Hai Whang
, p. 3944 - 3950 (2008/09/21)
The reactions of ethyl Y-phenyl chloro (1) and chlorothio (2) phosphates with X-anilines in acetonitrile at 55.0 °C are studied kinetically and theoretically. Kinetic results yield the primary kinetic isotope effects (k H/kD = 1.07-1.80 and 1.06-1.27 for 1 and 2, respectively) with deuterated aniline (XC6H4ND2) nucleophiles, and the cross-interaction constants ρXY = -0.60 and -0.28 for 1 and 2, respectively. A concerted mechanism involving a partial frontside attack through a hydrogen-bonded, four-center-type transition state is proposed. The large ρX (ρnuc = -3.1 to -3.4) and βX (βnuc = 1.1-1.2) values seem to be characteristic of the anilinolysis of phosphates and thiophosphates with the Cl leaving group. Because of the relatively large size of the aniline nucleophile, the degree of steric hindrance could be the decisive factor that determines the direction of the nucleophilic attack to the phosphate and thiophosphate substrates with the relatively small-sized Cl leaving group. This journal is The Royal Society of Chemistry.
