Kinetics and Mechanism of the Pyridinolyses of O-Methyl and O-Ethyl Phenyl Phosphonochloridothioates in Acetonitrile

Title
Kinetics and Mechanism of the Pyridinolyses of O-Methyl and O-Ethyl Phenyl Phosphonochloridothioates in Acetonitrile
Authors
이해황
Issue Date
2013
Publisher
INTERNATIONAL JOURNAL OF CHEMICAL KINETICS
Series/Report no.
INTERNATIONAL JOURNAL OF CHEMICAL KINETICS ; Vol45 no.5 Startpage 337 Endpage 342
Abstract
Kinetic studies on the reactions of O-methyl (2)andO-ethyl (3) phenyl phos-phonochloridothioates with X-pyridines have been carried out in acetonitrile at 35.0?C. Thepyridinolysis rates of 2 are slightly faster than those of 3. The substituent effects of X onthe pyridinolysis rates of 2 and 3 are similar. The Hammett and Br¨onsted plots with Xin the nucleophiles are biphasic concave upward with a break point at X = 3-Ph for bothsubstrates. The stepwise mechanism with rate-limiting leaving group departure from the in-termediate is proposed based on the βXvalues and biphasic concave upward free energyrelationship for both substrates. The biphasic concave upward free energy relationships arerationalized by a frontside nucleophilic attack TSf with more basic pyridines and backside at-tack TSb with less basic pyridines for both substrates.
URI
http://dspace.inha.ac.kr/handle/10505/33111
ISSN
0538-8066
Appears in Collections:
College of Natural Science(자연과학대학) > Chemistry (화학) > Local Access Journal Papers, Reports(화학 논문, 보고서)

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