56790-60-4Relevant articles and documents
Mechanism of the Hydrolysis of o-Nitro- and o-Benzoylbenzeneselenenic Anhydrides
Kice, John L.,McAfee, Farrell,Slebocka-Tilk, Henryka
, p. 3100 - 3106 (1984)
The hydrolyses (eq 1) of o-nitro- (2a) and o-benzoylbenzeneselenenic (2b) anhydrides to the corresponding acids (1a and 1b) havebeen studied kinetically over a range of pH in a series of buffers in 60percent dioxane.Both hydrolyses require acid catalysis.
THE ANHYDRIDE STRUCTURE OF SEVERAL PREVIOUSLY REPORTED STABLE ARSENESELENENIC ACIDS
Kice, John L.,McAfee, Farrell,Slebocka-Tilk, Henryka
, p. 3323 - 3326 (1982)
The compounds previously reported to be the stable areneselenenic acids, o-nitro- (1a) and o-benzoylbenzeneselenenic acid (1b), are shown actually to be the corresponding selenenic anhydrides (ArSeOSeAr).Solutions of the selenenic acids (ArSeOH), however,
Modelling the Inhibition of Selenoproteins by Small Molecules Using Cysteine and Selenocysteine Derivatives
Reddy, Kishorkumar M.,Mugesh, Govindasamy
, p. 8875 - 8883 (2019/06/17)
Small molecule-based electrophilic compounds such as 1-chloro-2,4-dinitrobenzene (CDNB) and 1-chloro-4-nitrobenzene (CNB) are currently being used as inhibitors of cysteine- and selenocysteine-containing proteins. CDNB has been used extensively to determine the activity of glutathione S-transferase and to deplete glutathione (GSH) in mammalian cells. Also, CDNB has been shown to irreversibly inhibit thioredoxin reductase (TrxR), a selenoenzyme that catalyses the reduction of thioredoxin (Trx). Mammalian TrxR has a C-terminal active site motif, Gly-Cys-Sec-Gly, and both the cysteine and selenocysteine residues could be the targets of the electrophilic reagents. In this paper we report on the stability of a series of cysteine and selenocysteine derivatives that can be considered as models for the selenoenzyme–inhibitor complexes. We show that these derivatives react with H2O2 to generate the corresponding selenoxides, which undergo spontaneous elimination to produce dehydroalanine. In contrast, the cysteine derivatives are stable towards such elimination reactions. We also demonstrate, for the first time, that the arylselenium species eliminated from the selenocysteine derivatives exhibit significant redox activity by catalysing the reduction of H2O2 in the presence of GSH (GPx (glutathione peroxidase)-like activity), which suggests that such redox modulatory activity of selenium compounds may have a significant effect on the cellular redox state during the inhibition of selenoproteins.
The pKa of Areneselenenic Acids
Kang, Sang-Ihn,Kice, John L.
, p. 287 - 290 (2007/10/02)
The pKa's of o-nitrobenzeneselenenic acid (1a) and three 4-substituted-2-nitrobenzeneselenenic acids (1b-d) heve been determined at 25 deg C in water.A Hammett plot of the pKa's gives a ρ value for the ionization of ArSeOH (eq 3) of
Mechanism of the Facile Formation and Hydrolysis of Esters of o-Nitrobenzeneselenenic Acid: New Insight into the Mechanism of Nucleophilic Substitution Reactions of o-Nitrobenzeneselenenyl Derivatives
Kang, Sang-Ihn,Kice, John L.
, p. 295 - 301 (2007/10/02)
o-Nitrobenzeneselenenic acid (1) undergoes rapid acid-catalyzed esterification by alcohols to afford alkyl o-nitrobenzeneselenenates, o-O2NC6H4SeOR (2), in high yield.The mechanism of esterification of 1 and of its reverse, the hydrolysis of 2, has been i
Rates of Oxidation of o-Nitrobenzeneselenenyl Compounds by m-Chloroperoxybenzoic Acid and the Rate of Reaction of o-Nitrobenzeneselenol with o-Nitrobenzeneselenenic Acid
Kice, John L.,Chiou, Shishue
, p. 290 - 294 (2007/10/02)
Rate constants for the oxidation of a series of o-nitrobenzeneselenenyl derivatives (Ar = o-O2NC6H4) by m-chloroperoxybenzoic acid (MCPBA) have been measured at 25 deg C in ethanol (compound, kPA (M-1s-1)): ArSeH, 1.1 * 104; ArSeOH, 80; ArSeOSeAr, 12; ArSeOEt, 4; ArSeSeAr, 0.15.The rate constant (kArSeH = 1.0 * 102 M-1s-1) for the reaction of ArSeH with ArSeOH to give ArSeSeAr (eq 3), which is pH independent in acid solution, has also been determined.Significant practical consequences of these and related results include the following: (a) the rate of oxidation of selenol (ArSeH) to selenenic acid (ArSeOH) is enough faster than either the oxidation of ArSeOH to seleninic acid (ArSeO2H) or eq 3 so that oxidation of the selenol with 1 molar equiv of MCPBA gives ArSeOH in high yield; (b) with a weaker oxidant, hydrogen peroxide, the rate of oxidation of the selenol is enough slower than the rate of eq 3 that the diselenide (ArSeSeAr) becomes the almost exclusive product; (c) the rate of oxidation of the diselenide is so much smaller than that of any of the other compounds that its initial oxidation to ArSeOSeAr is far and away the slowest step in its overall oxidation to seleninic acid by excess peracid.
The Equilibrium between an Areneselenic Acid and Its Anhydride
Kang, Sang-Ihn,Kice, John L.
, p. 2968 - 2972 (2007/10/02)
The equilibrium constants (Keq = 2/) associated with the equilibrium (eq 1) between o-nitro- and o-benzoylbenzeneselenenic anhydrides (2a and 2b) and the corresponding selenenic acids (1a and 1b) have been determined in dioxane containing 0.25-1.5percent water.For the 2b-1b equilibrium, Keq = 0.16 (25 deg C) and ΔH0 = +0.6 kcal/mol.The equilibrium constant for the 2a-1a system is ca. 10 times larger.That ΔH0 for the hydrolysis of 2b is slightly endothermic contrasts sharply with the exothermic nature of the hydrolysis of most common acid anhydrides.The values of Keq for both 2b and 2a are such that conditions can easily be encountered in media of low water content, where a significant fraction of the selenenic anhydride will remain unhydrolyzed at equilibrium, a situation without precedent in the chemistry of typical acid anhydrides.
Mechanism of the Reaction of Thiols with o-Nitro- and o-Benzoylbenzeneselenenic Acids and Anhydrides
Kice, John L.,McAfee, Farrell,Slebocka-Tilk, Henryka
, p. 3106 - 3114 (2007/10/02)
The kinetics of the reaction of an alkanethiol (n-BuSH) with o-nitro- (1a) and o-benzoylbenzeneselenenic (1b) acids (eq 3) and with the corresponding selenenic anhydrides (eq 4, 2a and 2b) have been investigated over a range of pH in a series of buffers i
NEW INSIGHT IN THE SYNTHESIS AND REACTIVITY OF SELENENIC ACIDS
Labar, Daniel,Krief, Alain
, p. 1005 - 1008 (2007/10/02)
o-nitrophenyl selenic acid has been observed during the reduction of the corresponding seleninic acid with hypophosphorous acid.An acid catalysis was found essential for the addition of at least o-nitrophenyl selenic acid to olefins.
"STABLE" SELENENIC ACIDS
Reich, Hans J.,Willis, William W.,Wollowitz, Susan
, p. 3319 - 3322 (2007/10/02)
Two of the stable selenenic acids reported in the literature are actually other materials.
