Voltammetrische Untersuchungen einiger substituierter 5-Aryliden-2-thiohydantoine in nichtw��rigem Medium

Abou‐Elenien, G. M.; Ismail, Nagwa Abdallah; El‐Din, Asmaa A. Magd

doi:10.1007/bf00808274

Cited by 6 publications

(4 citation statements)

References 9 publications

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“…Reduction of 5 arylidene 2 thiohydantoins gave thiol A, which was isolated as the reaction product after prepara tive electrolysis (Scheme 5). 31 A similar mechanism of oxidation and reduction can be proposed for the pyridyl substituted thiohydantoins under consideration. To validate this hypothesis, we per Table 3.…”

Section: Resultsmentioning

confidence: 86%

“…1), which is consistent with the mechanism of reduction proposed earlier. 31 However, the orbitals of the lone pairs of the sulfur atoms make the major contribution to HOMO (see Fig. 1, a-f ).…”

Section: Resultsmentioning

confidence: 98%

“…Polarographic reduction of 5 benzylidene 2 thiohydantoins in aqueous or alcoholic media at a dropping mercury electrode was documented in several publications, 28-30 but the only voltammetric study of aryl substituted 5 benzylidene 2 thiohydantoins in an aprotic medium was published. 31 We studied the electrochemical behavior of ligands 1 and 3-9 and their complexes with metal chlorides by cyclic voltammetry (CV) and using a rotating disk elec trode (RDE) at glassy carbon (GC) and Pt electrodes and, in some cases, at an Au electrode in DMF solutions. The electrochemical oxidation and reduction potentials are given in Table 3.…”

Section: Resultsmentioning

confidence: 99%

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5-(Pyridylmethylidene)-substituted 2-thiohydantoins and their complexes with CuII, NiII, and CoII: Synthesis, electrochemical study, and adsorption on the cystamine-modified gold surface

et al. 2006

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A series of Cu II , Ni II , and Co II complexes with 5 (pyridylmethylidene) substituted 2 thiohydantoins (L) were synthesized by the reactions of the corresponding organic ligands with MCl 2 •nH 2 O. The resulting complexes have the composition LMCl 2 (M = Cu or Ni) or L 2 MCl 2 (M = Co). The reactions with N(3) unsubstituted thiohydantoins afford complexes containing four membered metallacycles, in which the metal ion is coordinated by the S and N(3) atoms of the thiohydantoin ligand. The reactions of N(3) substituted thiohydantoins give complexes in which the S and N(1) atoms are involved in coordination. Study by IR spectro scopy demonstrated that the pyridine nitrogen atom is not involved in coordination. Based on the results of electrochemical study of the ligands and complexes by cyclic voltammetry and calculation of their frontier orbitals by the PM3(tm) method, the mechanism of oxidation and reduction of these compounds was proposed. In the first reduction and oxidation steps, the metal atom in the copper and nickel complexes remains, apparently, intact, and these pro cesses occur with the involvement of the ligand fragments, viz., the coordinated thiohydantoin ligand and chloride anion, respectively. In the cobalt complexes, the first reduction step occurs at the ligand; the first oxidation state, at the metal atom. Measurements of the contact angle of aqueous wetting and electrochemical study demonstrated that carboxy containing 2 thiohydantoins and their complexes can be adsorbed on the cystamine modified gold sur face. The structures of the complexes on the surface differ from the structures of these com plexes in solution.

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

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5-(Pyridylmethylidene)-substituted 2-thiohydantoins and their complexes with CuII, NiII, and CoII: Synthesis, electrochemical study, and adsorption on the cystamine-modified gold surface

et al. 2006

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“…The role of the CAS substituent is unclear, but given the activity of analogs like 2a and 2b (Table 1, entries 11 and 12), it seems unlikely that the CAS is itself participating in the photochemistry; the role of the sulfur is more likely electronic. Indeed, it is known that the arylidene portion of 5-arylidene-2-thiohydantoins is readily reduced in one-electron transfer processes (24). Thus, one plausible mechanism could entail a nearby aromatic amino acid side chain (perhaps Phe-60; cf.…”

Section: Figmentioning

confidence: 99%

Photochemically enhanced binding of small molecules to the tumor necrosis factor receptor-1 inhibits the binding of TNF-α

Carter

Scherle

Muckelbauer

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

127

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The binding of tumor necrosis factor alpha (TNF-α) to the type-1 TNF receptor (TNFRc1) plays an important role in inflammation. Despite the clinical success of biologics (antibodies, soluble receptors) for treating TNF-based autoimmune conditions, no potent small molecule antagonists have been developed. Our screening of chemical libraries revealed that N -alkyl 5-arylidene-2-thioxo-1,3-thiazolidin-4-ones were antagonists of this protein–protein interaction. After chemical optimization, we discovered IW927, which potently disrupted the binding of TNF-α to TNFRc1 (IC 50 = 50 nM) and also blocked TNF-stimulated phosphorylation of Iκ-B in Ramos cells (IC 50 = 600 nM). This compound did not bind detectably to the related cytokine receptors TNFRc2 or CD40, and did not display any cytotoxicity at concentrations as high as 100 μM. Detailed evaluation of this and related molecules revealed that compounds in this class are “photochemically enhanced” inhibitors, in that they bind reversibly to the TNFRc1 with weak affinity ( ca. 40–100 μM) and then covalently modify the receptor via a photochemical reaction. We obtained a crystal structure of IV703 (a close analog of IW927) bound to the TNFRc1. This structure clearly revealed that one of the aromatic rings of the inhibitor was covalently linked to the receptor through the main-chain nitrogen of Ala-62, a residue that has already been implicated in the binding of TNF-α to the TNFRc1. When combined with the fact that our inhibitors are reversible binders in light-excluded conditions, the results of the crystallography provide the basis for the rational design of nonphotoreactive inhibitors of the TNF-α–TNFRc1 interaction.

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Voltammetric Studies on Some Azoles and Their Derivatives

2001

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The redox characteristics of three series namely 5‐phenylmethylene‐2‐phenylhydrazonothiazolidin‐4‐ones, 3‐phenyl‐8‐oxobenzylidenthiazoles‐(2,3‐c)triazoles and ethyl‐2‐phenylhydrazono‐2‐benzimidazol‐2‐ylacetate has been investigated in nonaqueous acetonitrile, 1,2‐dichloroethane, tetrahydrofuran and dimethylsulfoxide at platinium and gold electrodes. Through controlled potential electrolysis, the oxidation and reduction products of each class of compounds can be separated and identified. The redox mechanism is suggested and proved.

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Voltammetrische Untersuchungen einiger substituierter 5-Aryliden-2-thiohydantoine in nichtw��rigem Medium

Cited by 6 publications

References 9 publications

5-(Pyridylmethylidene)-substituted 2-thiohydantoins and their complexes with CuII, NiII, and CoII: Synthesis, electrochemical study, and adsorption on the cystamine-modified gold surface

5-(Pyridylmethylidene)-substituted 2-thiohydantoins and their complexes with CuII, NiII, and CoII: Synthesis, electrochemical study, and adsorption on the cystamine-modified gold surface

Photochemically enhanced binding of small molecules to the tumor necrosis factor receptor-1 inhibits the binding of TNF-α

Voltammetric Studies on Some Azoles and Their Derivatives

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