Kinetics and mechanism of the aminolysis of O-ethyl S-aryl dithiocarbonates in acetonitrile

Oh, Hyuck Keun; Lee, Jun Yong; Yun, Jeong Hwan; Park, Sung Chul; Lee, Ikchoon

doi:10.1002/(sici)1097-4601(1998)30:6<419::aid-kin4>3.0.co;2-v

Cited by 37 publications

(4 citation statements)

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“…This means that the change of amine from secondary to tertiary amines leads to an increase in the magnitude of ␤ X . On the other hand, the aminolysis of O-ethlyl S-(Z-phenyl) dithiocarbonate (structure III with R ϭ EtO and Ar ϭ C 6 H 4 Z) with anilines in acetonitrile at 30.0ЊC was found to proceed by a concerted mechanism (␤ X ϭ 0.5 ϳ 0.7 and XZ ϭ -0.56) [20]. The cross-interaction constant, XZ , in the present work is determined by multiple regression of 20 k 2 [k XZ in Eqs.…”

Section: Resultsmentioning

confidence: 99%

Kinetics and mechanism of the aminolysis ofO-ethylS-aryl thiocarbonates in acetonitrile

Lee

2000

Int. J. Chem. Kinet.

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The kinetics and mechanism of the reactions of O-ethyl S-(Z)aryl thiocarbonates with (X)benzylamines in acetonitrile at 45.0ЊC are studied. Relatively small values of ␤ X (␤ nuc ) ϭ 0.6 ϳ 0.8 and ␤ Z (␤ lg ) ϭ Ϫ0.5 ϳ Ϫ0.7 together with a negative cross-interaction constant XZ (ϭ Ϫ0.47) and failure of the reactivity-selectivity principle (RSP) are interpreted to indicate a concerted mechanism. The normal kinetic isotope effects (k H /k D ϭ 1.3 ϳ 1.8) involving deuterated benzylamine nucleophiles suggest a hydrogen-bonded, four-center-type transition state.

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Section: Resultsmentioning

confidence: 99%

Kinetics and mechanism of the aminolysis ofO-ethylS-aryl thiocarbonates in acetonitrile

Lee

2000

Int. J. Chem. Kinet.

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“…The value of β = 0.87 obtained for the anilinolysis of 4 is in accordance with those found in similar reactions where the mechanism is stepwise and the nucleofuge is expelled from the tetrahedral intermediate as the rate determining step (0.8‐1.1) …”

Section: Resultsmentioning

confidence: 99%

“…The kinetics and mechanisms of the aminolysis of alkyl aryl and diaryl carbonates and some of their sulfur derivatives, such as O ‐alkyl S ‐aryl dithiocarbonates, are well documented . On the other hand, the mechanism of the aminolysis of O ‐aryl S ‐aryl dithiocarbonates has been extensively studied by us (Scheme ) .…”

Section: Introductionmentioning

confidence: 99%

The reactions of O‐(4‐nitrophenyl) S‐aryl dithiocarbonates with anilines: Effects on the relative nucleofugality

Santos

Gazitúa

2018

J of Physical Organic Chem

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Kinetic and high‐performance liquid chromatography studies were investigated for the reactions of S‐phenyl, S‐(4‐chlorophenyl), and S‐(4‐nitrophenyl) O‐(4‐nitrophenyl) dithiocarbonates with anilines. These were performed in the presence of 0.1M borate buffer in 44 wt% aqueous ethanol. For reactions of the 3 substrates, the mechanism is stepwise with 2 tetrahedral intermediates, one zwitterionic (T±), and the other anionic (T−), where the intermediate T− is formed by proton transfer from T± to the borate buffer. The nonleaving group is not passive, playing an important role in the relative nucleofugality of the groups, which depend largely on its electron withdrawing capability. The nucleofugacity of 4‐nitrophenolate ion and of 4‐nitrophenylthiolate from the same tetrahedral intermediate is similar, despite the differences in their basicities (3 pKa units). In the reactions of S‐(4‐nitrophenyl) O‐(4‐nitrophenyl) dithiocarbonate, the change of nucleophile from pyridines (only 4‐nitrophenolate ion is nucleofuge) to anilines (2 nucleofuges) shows that the nature of the amine impacts on the relative nucleofugality of groups.

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“…The kinetics and mechanisms of the aminolysis of O ‐alkyl S ‐aryl dithiocarbonates are well documented 1–4. Among these reports are those of the reactions of S ‐(2,4‐dinitrophenyl) and S ‐(2,4,6‐trinitrophenyl) O ‐ethyl dithiocarbonates with pyridines and secondary alicyclic (SA) amines in water, which proceed by a stepwise mechanism, through a zwitterionic tetrahedral intermediate (T ± ) 1.…”

Section: Introductionmentioning

confidence: 99%

Reactions of O‐aryl S‐aryl dithiocarbonates with secondary alicyclic amines in aqueous ethanol. Kinetics and mechanism

Castro

Gazitúa

Santos

2010

J of Physical Organic Chem

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The reactions of O‐(4‐methylphenyl) S‐(4‐nitrophenyl), O‐(4‐chlorophenyl) (4‐nitrophenyl), O‐(4‐chlorophenyl) S‐phenyl, and O‐(4‐methylphenyl) S‐phenyl dithiocarbonates (1, 2, 3, and 4, respectively) with a series of secondary alicyclic (SA) amines are subjected to a kinetic investigation in 44 wt% ethanol‐water, at 25.0 °C and an ionic strength of 0.2 M. The reactions are followed spectrophotometrically. Under amine excess, pseudo‐first‐order rate coefficients (kobs) are found. For some of the reactions, plots of kobs vs. free amine concentration at constant pH are linear but others are nonlinear upwards. This kinetic behavior is in accordance with a stepwise mechanism with two tetrahedral intermediates, one zwitterionic (T±) and the other anionic (T−). In some cases, there is a kinetically significant proton transfer from T± to an amine to yield T−. Values of the rate micro constants k1 (amine attack to form T±), k−1 (its back step), k2 (nucleofuge expulsion from T±), and k3 (proton transfer from T± to the amine) are determined for some reactions. The Brønsted plots for k1 are linear with slopes β1 = 0.2–0.4 in accordance with the slope values found when T± formation is the rate‐determining step. The sensitivity of log k1 and log k−1 to the pKa of the amine, leaving and non‐leaving groups are determined by a multiparametric equation. For the reactions of 1–4 with 1‐formylpiperazine and those of 3 and 4 with morpholine the k2 and k3 steps are rate determining. Copyright © 2010 John Wiley & Sons, Ltd.

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Kinetics and mechanism of the aminolysis of O-ethyl S-aryl dithiocarbonates in acetonitrile

Abstract: The aminolysis reactions of O-ethyl S-(Z-phenyl) dithiocarbonates ( H, Z ϭ p-CH , 3

Cited by 37 publications

References 14 publications

Kinetics and mechanism of the aminolysis ofO-ethylS-aryl thiocarbonates in acetonitrile

Kinetics and mechanism of the aminolysis ofO-ethylS-aryl thiocarbonates in acetonitrile

The reactions of O‐(4‐nitrophenyl) S‐aryl dithiocarbonates with anilines: Effects on the relative nucleofugality

Reactions of O‐aryl S‐aryl dithiocarbonates with secondary alicyclic amines in aqueous ethanol. Kinetics and mechanism

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