scholarly journals Kinetics of base hydrolysis of α-amino acid esters catalyzed by palladium(II) piperazine complex

2010 ◽  
Vol 8 (4) ◽  
pp. 797-805 ◽  
Author(s):  
Azza Shoukry ◽  
Mohamed Shoukry ◽  
Mohamed Hafez
Keyword(s):  
Kinetic Data ◽  
Methyl Esters ◽  
Activation Parameters ◽  
Base Hydrolysis ◽  
Amino Acid Esters ◽  
One Step ◽  
Glycine Methyl Ester ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Acid Esters

AbstractThe kinetics of base hydrolysis of glycine, histidine, and methionine methyl esters in the presence of [Pd(pip)(H2O)2]2+ complex, where pip is piperazine, is studied in aqueous solutions, at T = 25°C, and I = 0.1 mol dm−3. The rate of ester hydrolysis for glycine methyl ester is studied at different temperature and dioxane/water solutions of different compositions. The kinetic data are fit under the assumption that the hydrolysis proceeds in one step. The activation parameters for the base hydrolysis of the complexes are evaluated

Kinetics of base hydrolysis of α-amino acid esters catalyzed by [Pd(Et4en)(H2O)2]2+

2010 ◽  
Vol 63 (14-16) ◽  
pp. 2498-2506 ◽  
Author(s):  
Mohamed M. Shoukry ◽  
Abdul Aziz Al-Najjar ◽  
Wafaa M. Hosny ◽  
Afkar K. Abdel Hadi ◽  
Afaf A. Mahgoub ◽  
...  
Keyword(s):  
Amino Acid ◽  
Base Hydrolysis ◽  
Amino Acid Esters ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Acid Esters

The Effect of N-Substitution on the Rates of Saponification of Some Amino Acid Esters

1971 ◽  
Vol 49 (21) ◽  
pp. 3468-3476 ◽  
Author(s):  
Jocelyn E. Purdie ◽  
N. Leo Benoiton
Keyword(s):  
Amino Acid ◽  
Methyl Esters ◽  
Activation Parameters ◽  
Side Chain ◽  
Amino Acid Esters ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans ◽  
Hydrolysis Of ◽  
Acid Esters

The saponification rates (measured at 25 ° by a titrimetric method) of the unprotonated forms of the methyl esters of glycine, alanine, leucine, valine, and phenylalanine were compared with those of the N-methyl, the N-acetyl, and the N-acetyl, N-methylamino acid analogues. N-Acetylation slightly increased or decreased the rate but N-methylation caused a reduction by as much as a factor of ten, depending on the complexity of the side-chain. The esters of the N-acetyl, N-methylamino acids, which exist as cis and trans isomers, were saponified at rates intermediate between those of the esters of the N-acetylamino acids and N-methylamino acids. Activation parameters were obtained for the phenylalanine and leucine derivatives. N-Methylation resulted in an increase in ΔH≠ and ΔS≠ which was attributed in part to solvation effects. The hydrolysis of the cationic esters of glycine and alanine was still evident at pH 11.0. N-Methylation had little effect on the rates of saponification of the charged forms.

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