540517-75-7Relevant academic research and scientific papers
Kinetics and mechanism of the anilinolysis of 1,2-phenylene phosphorochloridate in acetonitrile
Barai, Hasi Rani,Lee, Hai Whang
scheme or table, p. 3355 - 3360 (2012/01/13)
The nucleophilic substitution reactions of 1,2-phenylene phosphorochloridate (1) with substituted anilines (XC6H 4NH2) and deuterated anilines (XC6H4ND2) are investigated kinetically in acetonitrile at -15.0 °C. The studied substrate of 1,2-phenylene phosphor°Chloridate is cyclic five-membered ring of phosphorus ester, and the anilinolysis rate of 1 is much faster than its acyclic analogue (4: ethyl phenyl chlorophosphate) because of extremely small magnitude of the entropy of activation of 1 compared to 4. The Hammett and Broensted plots exhibit biphasic concave upwards for substituent X variations in the nucleophiles with a break point at X = 3- Me. The values of deuterium kinetic isotope effects (DKIEs; kH/kD) change from secondary inverse (kH/kD 1) with the weakly basic anilines. The secondary inverse with the strongly basic anilines and primary normal DKIEs with the weakly basic anilines are rationalized by the transition state (TS) variation from a predominant backside attack to a predominant frontside attack, in which the reaction mechanism is a concerted SN2 pathway. The primary normal DKIEs are substantiated by a hydrogen bonded, four-center-type TS.
