(7-amino-8-methyl-phenothiazin-3-ylidene)-dimethyl-ammonium;2-methyl-3-dimethylamino-7-aminophenothiazin-5-ium;Toluidine Blue cation;toluidine blue O;Toluidine Blue;3-amino-7-dimethylamino-2-methyl-phenothiazinylium
Cu(II) catalyzed reaction between phenyl hydrazine and toluidine blue?dual role of acid
摘要:
The detailed kinetics of Cu(II) catalyzed reduction of toluidine blue (TB+) by phenyl hydrazine (Pz) in aqueous solution is studied. Toluidine white (TBH) and the diazonium ions are the main products of the reaction. The diazonium ion further decomposes to phenol (PhOH) and nitrogen. At low concentrations of acid, H+ ion autocatalyzes the uncatalyzed reaction and hampers the Cu(II) catalyzed reaction. At high concentrations, H+ hinders both the uncatalyzed and Cu(II) catalyzed reactions. Cu(II) catalyzed had stoichiometry similar to the uncatalyzed reaction, Pz + 2 TB+ + H2O = PhOH + 2 TBH + 2 H+ + N-2, Cu(II) catalyzed reaction occurs possibly through ternary complex formation between the unprotonated toluidine blue and phenyl hydrazine and catalyst. The rate coefficient for the Cu(II) catalyzed reaction is 2.1 X 10(4) M-2 s(-1). A detailed 13-step mechanistic scheme for the Cu(il) catalyzed reaction is proposed, which is supported by simulations, (C) 1999 John Wiley & Sons, Inc.
Mechanistic Implications of a Linear Free-Energy Correlation of Rate Constants for the Reduction of Active- and Met-R2 Forms of E. coli Ribonucleotide Reductase with Eight Organic Radicals
摘要:
Cross-reaction rate constants k(12) (22 degrees C) at pH 7.0 have been determined for the reduction of Fe-2(III) and tyrosyl-radical-containing active-R2 from E. coli ribonucleotide reductase with eight organic radicals (OR), e.g., MV.+ from methyl viologen. The more reactive OR's were generated in situ using pulse radiolysis (PR) techniques, and other OR's were generated by prior reduction of the parent with dithionite, followed by stopped-flow (SF) studies. In both procedures it was necessary to include consideration of doubly-reduced parent forms. Values of k(12) are in the range 10(9) to 10(4) M-1 s(-1) and reduction potentials E-1(o) for the OR vary from -0.446 to +0.194 V. Samples of E. coli active-R2 also have an Fe-2(III) met-R2 component (with no Tyr(.)), which in the present work was close to 40%. From separate experiments met-R2 gave similar kit rate constants ton average 66% bigger) to those for active-R2, suggesting that reduction of the Fe-2(III) center is the common rate-limiting seep. A single Marcus free-energy plot of log k(12) - 0.5 log f vs -E-1(o)/0.059 describes all the data, and the slope of 0.54 is in satisfactory agreement with the theoretical value of 0.50. It is concluded that the rate-limiting step involves electron transfer. In addition, the intercept at -E-1(o)/0.059 = 0 is 5.94, where values of the reduction potential and self-exchange rate constant for met-R2 contribute to this value. To maintain electroneutrality at the similar to 10 Angstrom buried active site H+ uptake is also required. For both e(-) and H+ transfer the conserved pathway Trp-48, Asp-237, His-118 to Fe-A is a possible candidate requiring further examination.
Fatty Acid Conjugates of Toluidine Blue O as Amphiphilic Photosensitizers: Synthesis, Solubility, Photophysics and Photochemical Properties
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作者:José Robinson‐Duggon、Nancy Pizarro、Germán Gunther、Daniel Zúñiga‐Núñez、Ana María Edwards、Alexander Greer、Denis Fuentealba
DOI:10.1111/php.13304
日期:2021.1
Toluidine blue O (TBO) is a water‐soluble photosensitizer that has been used in photodynamic antimicrobial and anticancer treatments, but suffers from limited solubility in hydrophobic media. In an effort to incrementally increase TBO’s hydrophobicity, we describe the synthesis of hexanoic (TBOC6) and myristic (TBOC14) fatty acid derivatives of TBO formed in low to moderate percent yields by condensation
Binding of toluidine blue-myristic acid derivative to cucurbit[7]uril and human serum albumin: computational and biophysical insights towards a biosupramolecular assembly
Simulated supramolecular and biomolecular interactions provide insights on ternary photosensitizer-cucurbit[n]uril–protein complex formation.
模拟超分子和生物分子相互作用有助于了解三元光敏剂-葫芦[n]葫芦-蛋白质复合物形成的机制。
Reduction of Toluidine Blue by Sulfur(IV) in Acetate Buffer Medium: Kinetics and Mechanism
作者:Pratik K. Sen、Rabindra N. Bera、Biswajit Pal
DOI:10.14233/ajchem.2015.18285
日期:——
The reduction of toluidine blue (TB+) by sulfite [S(IV)] was studied spectrophtometrically in acetic acid-sodium acetate buffer medium in the temperature range 293-308 K. The reaction showed first order dependence on toluidine blue. The reaction was found to be first order in S(IV) at lower substrate concentration ([S(IV)] £ 0.07 mol dm-3) but the reaction became second order in S(IV) at high substrate concentration ([S(IV)] > 0.07 mol dm-3). H+ ions were found to inhibit the reaction in the pH range 4.0-5.4. The rate decreased with increase in the ionic strength of the medium, but remained unchanged with decreasing dielectric constant of the medium. The oxidation reaction possibly involved a one-electron transfer step via a free radical mechanism. An overall enthalpy and entropy of activation were computed. A plausible mechanism and rate law corroborating the experimental results have been put forward.
Thiol-reacting toluidine blue derivatives: Synthesis, photophysical properties and covalent conjugation with human serum albumin
作者:Nory Mariño-Ocampo、Juan S. Reyes、Germán Günther、Belinda Heyne、Denis Fuentealba
DOI:10.1016/j.dyepig.2022.110225
日期:2022.5
characterized toluidine blue (TBO) derivates directed towards forming a covalent conjugation with human serum albumin (HSA) as a delivery vehicle under physiologically relevant conditions. We described herein the synthesis of 3-(2-pyridyldithio)propionate (PDP) and 6-maleimidocaproate (EMC) derivatives of TBO (TBOPDP and TBOEMC, respectively), their photophysical/photochemical properties and reactivity towards
The invention relates generally to the use of diaminophenothiazine compounds to inhibit or reverse the aggregation of synuclein, and for their use in the manufacture of medicaments for this purpose (e.g. for the treatment of Parkinson's Disease). Also provided are related methods of detecting or labelling of aggregated synuclein.