Role of the Metal Center in the Homogeneous Catalytic Decarboxylation of Select Carboxylic Acids. Copper(I) and Zinc(II) Derivatives of Cyanoacetate

1995 ◽  
Vol 117 (1) ◽  
pp. 318-328 ◽  
Author(s):  
Donald J. Darensbourg ◽  
Matthew W. Holtcamp ◽  
Elisabeth M. Longridge ◽  
Bandana Khandelwal ◽  
Kevin K. Klausmeyer ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Metal Center ◽  
Derivatives Of ◽  
Catalytic Decarboxylation

Reversible decarboxylation of phosphine derivatives of Cu(I) cyanoacetate. Mechanistic aspects germane to catalytic decarboxylation of carboxylic acids

1993 ◽  
Vol 115 (19) ◽  
pp. 8839-8840 ◽  
Author(s):  
Donald J. Darensbourg ◽  
Elisabeth M. Longridge ◽  
Matthew W. Holtcamp ◽  
Kevin K. Klausmeyer ◽  
Joseph H. Reibenspies
Keyword(s):  
Carboxylic Acids ◽  
Phosphine Derivatives ◽  
Derivatives Of ◽  
Catalytic Decarboxylation

The role of secondary alcoholic groups of D-galacturonan in its degradation with exo-D-galacturonanase

1980 ◽  
Vol 45 (2) ◽  
pp. 427-434 ◽  
Author(s):  
Kveta Heinrichová ◽  
Rudolf Kohn
Keyword(s):  
Acetyl Derivative ◽  
Competitive Inhibitor ◽  
Hydroxyl Groups ◽  
Pectic Acid ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
The Individual ◽  
Degradation Degree ◽  
Derivatives Of

The effect of exo-D-galacturonanase from carrot on O-acetyl derivatives of pectic acid of variousacetylation degree was studied. Substitution of hydroxyl groups at C(2) and C(3) of D-galactopyranuronic acid units influences the initial rate of degradation, degree of degradation and its maximum rate, the differences being found also in the time of limit degradations of the individual O-acetyl derivatives. Value of the apparent Michaelis constant increases with increase of substitution and value of Vmax changes. O-Acetyl derivatives act as a competitive inhibitor of degradation of D-galacturonan. The extent of the inhibition effect depends on the degree of substitution. The only product of enzymic reaction is D-galactopyranuronic acid, what indicates that no degradation of the terminal substituted unit of O-acetyl derivative of pectic acid takes place. Substitution of hydroxyl groups influences the affinity of the enzyme towards the modified substrate. The results let us presume that hydroxyl groups at C(2) and C(3) of galacturonic unit of pectic acid are essential for formation of the enzyme-substrate complex.

Anomalous narrowing of the shape of the structural process in derivatives of trehalose at high pressure. The role of the internal structure

2021 ◽  
pp. 116321
Author(s):  
Dawid Heczko ◽  
Joanna Grelska ◽  
Karolina Jurkiewicz ◽  
Patrycja Spychalska ◽  
Anna Kasprzycka ◽  
...  
Keyword(s):  
High Pressure ◽  
Internal Structure ◽  
Structural Process ◽  
Derivatives Of

scholarly journals Enzymatic synthesis and phosphorolysis of 4(2)-thioxo- and 6(5)-azapyrimidine nucleosides by E. coli nucleoside phosphorylases

2016 ◽  
Vol 12 ◽  
pp. 2588-2601 ◽  
Author(s):  
Vladimir A Stepchenko ◽  
Anatoly I Miroshnikov ◽  
Frank Seela ◽  
Igor A Mikhailopulo
Keyword(s):  
Purine Nucleoside Phosphorylase ◽  
Reaction Conditions ◽  
E Coli ◽  
No Formation ◽  
Structural Peculiarities ◽  
Substrate Properties ◽  
Nucleoside Phosphorylases ◽  
Derivatives Of

The trans-2-deoxyribosylation of 4-thiouracil (4SUra) and 2-thiouracil (2SUra), as well as 6-azauracil, 6-azathymine and 6-aza-2-thiothymine was studied using dG and E. coli purine nucleoside phosphorylase (PNP) for the in situ generation of 2-deoxy-α-D-ribofuranose-1-phosphate (dRib-1P) followed by its coupling with the bases catalyzed by either E. coli thymidine (TP) or uridine (UP) phosphorylases. 4SUra revealed satisfactory substrate activity for UP and, unexpectedly, complete inertness for TP; no formation of 2’-deoxy-2-thiouridine (2SUd) was observed under analogous reaction conditions in the presence of UP and TP. On the contrary, 2SU, 2SUd, 4STd and 2STd are good substrates for both UP and TP; moreover, 2SU, 4STd and 2’-deoxy-5-azacytidine (Decitabine) are substrates for PNP and the phosphorolysis of the latter is reversible. Condensation of 2SUra and 5-azacytosine with dRib-1P (Ba salt) catalyzed by the accordant UP and PNP in Tris∙HCl buffer gave 2SUd and 2’-deoxy-5-azacytidine in 27% and 15% yields, respectively. 6-Azauracil and 6-azathymine showed good substrate properties for both TP and UP, whereas only TP recognizes 2-thio-6-azathymine as a substrate. 5-Phenyl and 5-tert-butyl derivatives of 6-azauracil and its 2-thioxo derivative were tested as substrates for UP and TP, and only 5-phenyl- and 5-tert-butyl-6-azauracils displayed very low substrate activity. The role of structural peculiarities and electronic properties in the substrate recognition by E. coli nucleoside phosphorylases is discussed.

Role of metal center and coordination environment in M-(Z)-N-((E)-pyridin-2-ylmethylene)isonicotinohydrazonate (M = LaIII, ZnII, CdII or HgII) catalyzed cyanosilylation of aldehydes

Polyhedron ◽  
2021 ◽  
Vol 209 ◽  
pp. 115453
Author(s):  
Fatali E. Huseynov ◽  
Ghodrat Mahmoudi ◽  
Sevinc R. Hajiyeva ◽  
Nazim T. Shamilov ◽  
Fedor I. Zubkov ◽  
...  
Keyword(s):  
Metal Center ◽  
Coordination Environment

On the Mechanism of Catalytic Decarboxylation of Carboxylic Acids on Carbon-Supported Palladium Hydride

ACS Catalysis ◽  
2021 ◽  
pp. 14625-14634
Author(s):  
Fuli Deng ◽  
Juanjuan Huang ◽  
Erika E. Ember ◽  
Klaus Achterhold ◽  
Martin Dierolf ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Palladium Hydride ◽  
Supported Palladium ◽  
Catalytic Decarboxylation

ChemInform Abstract: Heterocyclic Analogues of 5,12-Naphthacenequinone. Part 12. Synthesis of 2-Substituted Derivatives of 4,11-Dimethoxy-5,10-dioxoanthra[2,3-b]furan-3-carboxylic Acids.

ChemInform ◽  
2014 ◽  
Vol 45 (44) ◽  
pp. no-no
Author(s):  
A. S. Tikhomirov ◽  
A. E. Shchekotikhin ◽  
Yu. N. Luzikov ◽  
A. M. Korolev ◽  
M. N. Preobrazhenskaya
Keyword(s):  
Carboxylic Acids ◽  
Derivatives Of

Heterocyclic Analogs of 5,12-Naphthacene-Quinone. 12. Synthesis of 2-Substituted Derivatives of 4,11-Dimethoxy-5,10-Dioxo-Anthra[2,3-b]Furan-3-Carboxylic Acids

2014 ◽  
Vol 50 (2) ◽  
pp. 271-280 ◽  
Author(s):  
A. S. Tikhomirov ◽  
A. E. Shchekotikhin ◽  
Yu. N. Luzikov ◽  
A. M. Korolev ◽  
M. N. Preobrazhenskaya
Keyword(s):  
Carboxylic Acids ◽  
Derivatives Of
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