Hydrolysis kinetics and mechanism of diarylthiocarbamates in 20% aqueous dioxane medium

1980 ◽  
Vol 45 (11) ◽  
pp. 3130-3139 ◽  
Author(s):  
Jaromír Mindl ◽  
Pavel Balcárek ◽  
Lubomír Šilar ◽  
Miroslav Večeřa

Substituted S-aryl and O-aryl N-arylthiocarbamates have been synthetized. Kinetic studies of hydrolysis of these compounds in 20% aqueous dioxane prove the E1cB mechanism. The found Hammett reaction constants, activation entropy values, Broensted coefficients, and comparison of reactivity with N-methyl analogues have been discussed as criteria of the mentioned mechanism. Hydrolysis results of thiocarbamates in the same medium are compared.

1981 ◽  
Vol 46 (8) ◽  
pp. 1970-1975 ◽  
Author(s):  
Jaromír Mindl ◽  
Jiří Sulzer ◽  
Miroslav Večeřa

Nine diaryldithiocarbamates have been prepared. Kinetic study of their hydrolysis has revealed that this hydrolysis proceeds by E1cB mechanism in the pH range 2 to 12. Values of activation entropies, reaction constants, Broensted coefficient, and comparison with reactivity of the corresponding N-methyl analogue have been used as criteria for the suggested mechanism. In acid media pH 2 to 0.4 and H0 -0.6 the hydrolysis follows a mechanism analogous to AAc2. Results of hydrolyses of dithiocarbamates, thiocarbamates and carbamates are compared.


1980 ◽  
Vol 45 (4) ◽  
pp. 1065-1071 ◽  
Author(s):  
Alexandr Čegan ◽  
Jaroslav Šlosar ◽  
Miroslav Večeřa

Hydrolysis of N' -(3-N-methylcarbamoyloxyphenyl)-N,N-dimethylformamidine (I) has been studied in mixture water-dioxane (4 : 1) at pH 1 to 13. The hydrolysis rates of methylcarbamoyl and dimethylformamidine groups are comparable within pH range 4 to 10, and they differ by as much as several orders of magnitude in pH ranges 1-3 and 11-13. The hydrolysis products of the whole pH range have been determined by paper chromatography, and reaction mechanism has been suggested on the basis of the measured hydrolysis rate constants.Effects of protonation and hydratation of dimethylformamidine group on the hydrolysis rate of the methylcarbamoyl group is discussed.


1976 ◽  
Vol 7 (40) ◽  
pp. no-no
Author(s):  
TAE-RIN KIM ◽  
JIN-HEE KIM ◽  
BYUNG-DOO CHANG ◽  
KWANG-IL LEE ◽  
UNG-CHO KIM

1969 ◽  
Vol 8 (11) ◽  
pp. 2504-2508 ◽  
Author(s):  
William Edward Jones ◽  
Robert B. Jordan ◽  
T. W. Swaddle

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