Conformational analysis of the complexes of copper(ii) with two identical ?-amino acid ligands, relative stability of the cis and trans isomers

1987 ◽  
Vol 36 (11) ◽  
pp. 2306-2309
Author(s):  
T. V. Timofeeva ◽  
A. A. Kurganov ◽  
V. A. Davankov ◽  
Yu. T. Struchkov
Keyword(s):  
Amino Acid ◽  
Conformational Analysis ◽  
Relative Stability ◽  
Trans Isomers ◽  
Identical Amino Acid ◽  
Cis And Trans Isomers ◽  
Cis And Trans

Reactivities of Piperazine-2,5-diones in Radical Bromination Reactions

1996 ◽  
Vol 49 (11) ◽  
pp. 1229 ◽  
Author(s):  
CLL Chai ◽  
DCR Hockless ◽  
AR King
Keyword(s):  
Crystal Structure ◽  
Amino Acid ◽  
Chemical Reactivity ◽  
Trans Isomers ◽  
Radical Bromination ◽  
Conformational Effects ◽  
Cis And Trans Isomers ◽  
The Difference ◽  
Cis And Trans

The reactivities of various N,N'- diacetylated piperazine-2,5-diones towards radical bromination reactions are reported. The studies show that glycyl centres of piperazine-2,5-diones are more reactive towards radical bromination reactions compared to α-substituted amino acid centres. In addition, large differences in reactivities were observed for the cis and trans isomers of N,N'-diacetylated alanine anhydride. Single-crystal structure determination of each isomer revealed that conformational effects may account for the difference in chemical reactivity.

Conformations, configurations, and proton reactions of colbalt(III) complexes

1967 ◽  
Vol 20 (2) ◽  
pp. 257 ◽  
Author(s):  
DA Buckingham ◽  
L Durham ◽  
AM Sargeson
Keyword(s):  
Amino Acid ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Proton Magnetic Resonance ◽  
Proton Magnetic Resonance Spectroscopy ◽  
Proton Exchange ◽  
Resonance Spectroscopy ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans

Proton magnetic resonance spectroscopy allows the cis and trans isomers of [CoX2 en2] complexes to be distinguished. Some information has been obtained concerning the rate of chelate conformational interchange for cobalt-ethylenediamine, propylenediamine, N-methylethylenediamine, and malonate rings. For [Co(amino acid)en2]2+ complexes the diastereoisomeric pairs can be differentiated and the relative rates of CH and NH proton exchange have been observed for a variety of chelate rings including cobalt-amino acid, acetylacetonato, ethylenediamine, and malonato.

Relative stability of the cis and trans isomers of octahedral cobalt(iii) complexes of the type [Co(N2O2)X2] with tetradentate salen type Schiff bases: a combined theoretical and experimental study

CrystEngComm ◽  
2019 ◽  
Vol 21 (40) ◽  
pp. 6026-6037
Author(s):  
Kousik Ghosh ◽  
Snehasis Banerjee ◽  
Shouvik Chattopadhyay
Keyword(s):  
Experimental Study ◽  
Dft Calculations ◽  
Schiff Bases ◽  
Relative Stability ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans

Energies of cis and trans isomers of a series of octahedral cobalt(iii) complexes with salen type Schiff bases have been estimated by DFT calculations.

Conformational analysis of cis- and trans-isomers of 2,5-dimethyl-1,3-dioxane

2009 ◽  
Vol 79 (12) ◽  
pp. 2673-2677 ◽  
Author(s):  
M. G. Faizullin ◽  
A. E. Kuramshina ◽  
A. Kh. Mamleev ◽  
V. V. Kuznetsov
Keyword(s):  
Conformational Analysis ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans

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.

The relative stability of cis and trans isomers

1995 ◽  
Vol 341 (1-3) ◽  
pp. 141-147 ◽  
Author(s):  
L.L. Boyle ◽  
R.F. Hudson ◽  
J.D. Wallis
Keyword(s):  
Relative Stability ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans
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