Immunochemical recognition of phosphate ester derivatives of phenol rings is dependent upon the electronic charge of the ester group

1986 ◽  
Vol 6 (3) ◽  
pp. 265-273 ◽  
Author(s):  
Jane A. Jones ◽  
Alison Wood ◽  
William Cushley
Keyword(s):  
Ph Value ◽  
Ester Group ◽  
Phosphate Esters ◽  
Phosphate Ester ◽  
Electronic Charge ◽  
Alkaline Phosphatases ◽  
Tyrosine Residues ◽  
Substrate Analogues ◽  
Tyrosine Phosphate ◽  
Derivatives Of

The recognition of phosphate and sulphate esters of tyrosine residues has been studied employing antisera with specificity for tyrosine phosphate, and the enzymes aryl sulphatase, and acid and alkaline phosphatases. The ability of tyrosine phosphate, and of phosphate esters of phenol, to inhibit the antiserum was pH dependent. The capacity to effect inhibition appeared to correlate with alterations in the ionisation of the inhibitor. Moreover, the antisera with reactivity for tyrosine phosphate had no reactivity with tyrosine sulphate or sulphate esters of phenol at any pH value studied. The enzymes alkaline phosphatase, acid phosphatase, and aryl sulphatase were also studied. The phosphatases were found not to hydrolyse sulphate ester containing substrate analogues at any pH value in the range 5.0–9.0. In contrast, aryl sulphatase appeared to hydrolyse phosphate esters at pH 5.0 and 7.0, but not at pH 9.0.

Substituent Effects on the Thermal Decomposition of Phosphate Esters on Ferrous Surfaces

2019 ◽  
Author(s):  
James Ewen ◽  
Carlos Ayestaran Latorre ◽  
Arash Khajeh ◽  
Joshua Moore ◽  
Joseph Remias ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Film Formation ◽  
Substituent Effects ◽  
Vapour Phase ◽  
Industrial Applications ◽  
Phosphate Esters ◽  
Antiwear Additives ◽  
Formation Mechanisms ◽  
Phosphate Ester ◽  
Wide Range

<p>Phosphate esters have a wide range of industrial applications, for example in tribology where they are used as vapour phase lubricants and antiwear additives. To rationally design phosphate esters with improved tribological performance, an atomic-level understanding of their film formation mechanisms is required. One important aspect is the thermal decomposition of phosphate esters on steel surfaces, since this initiates film formation. In this study, ReaxFF molecular dynamics simulations are used to study the thermal decomposition of phosphate esters with different substituents on several ferrous surfaces. On Fe<sub>3</sub>O<sub>4</sub>(001) and α-Fe(110), chemisorption interactions between the phosphate esters and the surfaces occur even at room temperature, and the number of molecule-surface bonds increases as the temperature is increased from 300 to 1000 K. Conversely, on hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>, most of the molecules are physisorbed, even at high temperature. Thermal decomposition rates were much higher on Fe<sub>3</sub>O<sub>4</sub>(001) and particularly α-Fe(110) compared to hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>. This suggests that water passivates ferrous surfaces and inhibits phosphate ester chemisorption, decomposition, and ultimately film formation. On Fe<sub>3</sub>O<sub>4</sub>(001), thermal decomposition proceeds mainly through C-O cleavage (to form surface alkyl and aryl groups) and C-H cleavage (to form surface hydroxyls). The onset temperature for C-O cleavage on Fe<sub>3</sub>O<sub>4</sub>(001) increases in the order: tertiary alkyl < secondary alkyl < primary linear alkyl ≈ primary branched alkyl < aryl. This order is in agreement with experimental observations for the thermal stability of antiwear additives with similar substituents. The results highlight surface and substituent effects on the thermal decomposition of phosphate esters which should be helpful for the design of new molecules with improved performance.</p>

Carboxylic acid and phosphate ester derivatives of fluconazole: synthesis and antifungal activities

2004 ◽  
Vol 12 (23) ◽  
pp. 6255-6269 ◽  
Author(s):  
Nguyen-Hai Nam ◽  
Soroush Sardari ◽  
Meredith Selecky ◽  
Keykavous Parang
Keyword(s):  
Carboxylic Acid ◽  
Phosphate Ester ◽  
Antifungal Activities ◽  
Derivatives Of

Reaktionsverhalten von β-Oxo-carbonsäurederivaten der Anthracenreihe bei der Synthese von Pyrazolen / On the Reaction Behavior of ß-Oxo Carbonic Acid Derivatives of the Anthracene Series in Pyrazole Synthesis

1999 ◽  
Vol 54 (9) ◽  
pp. 1133-1137
Author(s):  
Astrid Knieß ◽  
Margit Gruner ◽  
Roland Mayer
Keyword(s):  
Carbonyl Group ◽  
Carbonic Acid ◽  
Ester Group ◽  
Reaction Behavior ◽  
Anthracene Derivatives ◽  
Sterical Hindrance ◽  
Derivatives Of

ß-Oxo-1 and 9-anthracenepropionate (6 and 7) reacts with DMF-acetale to enaminones 10 and 11. The reaction of 2-(dimethylamino)methylen-substituted ß-oxo-1 -anthracenepropionate (10) with hydrazines yields 5-(l-anthracenyl)-pyrazol-4-carboxylates (13). In contrast, the cyclocondensation of 3-(9-anthracenyl)-2-(dimethylamino)methylen-3-oxo-propionate (11) with hydrazine hydrochlorides gives 4-(9-anthracenoyl)-5-hydroxy-pyrazoles (14). This is caused by the sterical hindrance of the carbonyl group of the anthracene derivatives in position 9; thus, the cyclocondensation proceeds via reaction of the ester group of the enaminone 11.

29Si-Kernresonanzuntersuchungen an N-Trimethylsilyl-substituierten Aminen und Amiden / 29Si Nuclear Magnetic Resonance Studies on N-Trimethylsilyl Derivatives of Amines and Amides

1977 ◽  
Vol 32 (2) ◽  
pp. 163-166 ◽  
Author(s):  
B. Heinz ◽  
H. C. Marsmann ◽  
U. Niemann
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Aromatic Amines ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Electronic Charge ◽  
Magnetic Resonance Studies ◽  
Basic Character ◽  
Silyl Derivatives ◽  
Trimethylsilyl Derivatives ◽  
Derivatives Of

The 29Si chemical shifts of several trimethyl silyl derivatives of amines and amides are measured and compared to other chemical and theoretical properties such as the basicities or the electronic charge on the nitrogen or the hydrogen of the N-H group of the amine or the amide. Whereas the 29Si chemical shift of saturated amines can be rationalized in terms of substituent effects, the shifts of aromatic amines show some dependency on the basic character of the amine. There seems to be little correlation between 29Si chemical shifts and electronic charge, but there is a similarity of 29Si with 1H chemical shifts of the NH group, which is interpreted as depending on anisotropy effects.

scholarly journals Purification and characterization of methionine γ-lyase from Trichomonas vaginalis

1991 ◽  
Vol 279 (3) ◽  
pp. 675-682 ◽  
Author(s):  
B C Lockwood ◽  
G H Coombs
Keyword(s):  
Molecular Mass ◽  
Trichomonas Vaginalis ◽  
Protozoan Parasite ◽  
Purification And Characterization ◽  
Native Molecular Mass ◽  
Substrate Analogues ◽  
Beta Elimination ◽  
Derivatives Of ◽  
Methionine Gamma Lyase

Methionine gamma-lyase (EC 4.4.1.11) was purified to homogeneity from the anaerobic protozoan parasite Trichomonas vaginalis by a series of f.p.l.c. procedures. The enzyme catalyses alpha gamma- and alpha beta-elimination reactions of a number of derivatives of methionine and cysteine. It also catalyses gamma-replacement reactions of the thiomethyl group of methionine, homocysteine and ethionine to yield the corresponding S-substituted homocysteine derivative. The enzyme is pyridoxal 5′-phosphate-dependent, has a native molecular mass of approx. 160 kDa and consists of four apparently identical subunits of molecular mass 43-45 kDa. The absorption spectrum of the enzyme is typical of those obtained for other pyridoxal 5′-phosphate-dependent enzymes, and the holoenzyme can be resolved to the apoenzyme by incubation with hydroxylamine and reconstituted by addition of the cofactor. The enzyme activity is significantly affected by carbonyl and thiol reagents, is competitively inhibited by a number of substrate analogues and is completely inactivated by the suicide inhibitor DL-propargylglycine. The T. vaginalis enzyme is similar, in terms of activity and properties, to the enzymes found in a number of species of bacteria that metabolize methionine under anaerobic conditions. It is suggested that methionine catabolism may be of particular importance to the survival of T. vaginalis under microaerophilic conditions in its host.

Oxy and thio phosphorus acid derivatives of tin. 9. Di- and triorganotin(IV) diphenyl phosphate esters

1982 ◽  
Vol 21 (5) ◽  
pp. 1711-1714 ◽  
Author(s):  
K. C. Molloy ◽  
F. A. K. Nasser ◽  
J. J. Zuckerman
Keyword(s):  
Phosphorus Acid ◽  
Phosphate Esters ◽  
Diphenyl Phosphate ◽  
Derivatives Of

THE RELATION BETWEEN PHOSPHATE METABOLISM AND THE TRANSPORT OF CATIONS ACROSS THE CELL MEMBRANE IN THE HUMAN ERYTHROCYTE

1961 ◽  
Vol 39 (12) ◽  
pp. 1879-1894
Author(s):  
Rhoda Blostein ◽  
David Rubinstein ◽  
Orville F. Denstedt
Keyword(s):  
Cell Membrane ◽  
Inorganic Phosphate ◽  
Phosphate Esters ◽  
Phosphate Ester ◽  
Red Cell ◽  
Phosphate Metabolism ◽  
Hydrogen Ions ◽  
Cation Composition ◽  
Red Cell Membrane ◽  
Rate Of Movement

The rate of passage of cations across the red cell membrane, in the direction of the respective ionic gradients, in blood preserved with glucose at 4 °C, is not diminished upon the addition of inosine, notwithstanding the induced formation of substantial amounts of phosphate esters, including ATP, in the cells. The movement of cations, however, is retarded on the addition of glucose or inorganic phosphate, and on increase in the concentration of hydrogen ions. It would appear, therefore, that the movement of cations across the membrane, at 4 °C, is influenced little, if at all, by the metabolic activity of the cell.When the temperature of the preserved blood is returned to 37° the rate of movement of cations across the cell membrane against their respective gradients is greatest in cells which had either been preserved or have been incubated with inosine even if the remainder of the inosine has been removed. Inosine is more effective than glucose in bringing about the restoration of cation composition in preserved red cells at 37°. The degree of restoration is greater in the presence of glucose than in its absence. Arsenate inhibits the transport of cations against the gradients. Evidence is given that the capacity of the cells to restore the cation distribution at 37 °C is determined largely by the concentration of the phosphate ester intermediates.

Pyrrolotriazine-5-carboxylate ester inhibitors of EGFR and HER2 protein tyrosine kinases and a novel one-pot synthesis of C-4 subsitituted pyrrole-2,3-dicarboxylate diesters

2006 ◽  
Vol 84 (4) ◽  
pp. 528-533 ◽  
Author(s):  
Harold Mastalerz ◽  
Ashvinikumar V Gavai ◽  
Brian Fink ◽  
Charles Struzynski ◽  
James Tarrant ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Kinase Inhibitors ◽  
Ester Group ◽  
Her2 Receptor ◽  
One Pot ◽  
Available N ◽  
Her2 Protein ◽  
Wittig Olefination ◽  
Derivatives Of ◽  
Acid Esters

Pyrrolotriazines with an ester group at C-5 were prepared and evaluated as inhibitors of the EGFR and HER2 receptor tyrosine kinases, validated targets for cancer therapy. The C-5 ester (15) was at least as potent as its C-6 ester analogue (17), an example of a known series of pyrrolotriazine EGRF/HER2 kinase inhibitors that show good biochemical and cellular activity. The C-5 esters were synthesized from pyrrole 2,3-diesters that were made by a new, one-pot procedure. This involved reaction of readily available N-tosyl derivatives of α-amino acid esters or ketones with triphenylphosphine and diethyl acetylenedicarboxylate to form 3-pyrrolines via an intramolecular Wittig olefination. The 3-pyrroline intermediates were not isolated but treated directly with base to eliminate toluenesulfinic acid and generate the pyrrole 2,3-diesters in good yield.Key words: pyrrolotriazine, EGFR, HER2, pyrrole, intramolecular Wittig reaction.

Phosphate ester derivatives of deuterohemin IX dimethyl ester

1972 ◽  
Vol 153 (1) ◽  
pp. 398-402
Author(s):  
C.S. Russell ◽  
J. Landis ◽  
N. Bocian
Keyword(s):  
Dimethyl Ester ◽  
Phosphate Ester ◽  
Derivatives Of

Bonding of Rubber to Metal by Means of New Chemical Derivatives of Rubber

1950 ◽  
Vol 23 (1) ◽  
pp. 281-291 ◽  
Author(s):  
Jacques Gossot
Keyword(s):  
Ph Value ◽  
Chemical Reactivity ◽  
Point Of View ◽  
Physical Point ◽  
General Application ◽  
Chemical Derivatives ◽  
Special Cases ◽  
Practical Standpoint ◽  
In Virtue Of ◽  
Derivatives Of

Abstract The bonding process which has been described is of general application to all types of rubber mixtures, to metals, and to various other materials, without any change in composition of the bonding agent for the different materials. Although the problem of adhesion has been approached in this work only from the purely practical standpoint, it should be realized how little progress has been made in the theoretical knowledge of the problem. As a matter of fact, only a few authors have attempted to explain, on a basis of general concepts, certain special cases of adhesion, and there is still no real insight into the problem as a whole which might open the way to material progress. If one turns to the works of MacBain, Delmonte, and Buchan among the most important contributions to the phenomena of adhesion, the ultimate conclusion must be drawn that little has been accomplished in orienting investigations in this field toward more productive ends. From the physical point of view, particular attention must be paid to the condition of the state of the surface of the material to be bonded, to the surface tension, to the viscosity, and to the pH value of the adhesive. The chemical structure of the latter is that of a long-chain compound and, as has been proved conclusively in the present investigation, certain groups play a fundamental role, both in virtue of their chemical reactivity, and in virtue of the polar moment which they confer upon the molecule.

Sign in / Sign up

Export Citation Format

Share Document