Kinetic studies on oxidations of leucomethylene blue and leucothionine by iron (III) in aqueous solution
摘要:
The reaction kinetics and mechanism of the oxidations of leucomethylene blue (MBH) and leucothionine (TH) by iron (III) sulfate in aqueous solution were studied spectrophotometrically by the stopped-flow technique. MBH and TH, which were freshly prepared by photoreduction of methylene blue and thionine, respectively, with ascorbic acid were used in the kinetic measurements. The pseudo-first-order rate constants (k(obsd)) show kinetic saturation at high initial concentrations of iron (III) sulfate for MBH and TH. It was found that the reciprocal of k(obsd) increases linearly with increase in the reciprocal of [Fe3+](0). A broad absorption band was observed on mixing MBH and Fe3+ solutions at low temperatures, and this was attributed to a charge-transfer complex between MBH and Fe3+. The effects of Fe2+ ion and L-(+)-ascorbic acid on the rates of oxidation were also investigated. A small kinetic isotope effect on the oxidation rate for MBH was observed. The results can be explained by a general mechanism with stepwise electron-proton-electron transfers with the formation of a complex between reactants. Copyright (C) 1999 John Wiley & Sons, Ltd.
Electrochemical study of the reaction between leucodye and FeIII in dye-based photogalvanic systems
作者:A. Surya N. Murthy、Tanuja Srivastava
DOI:10.1039/ft9908600105
日期:——
The electrochemical reduction of thionine and methylene blue in the presence of Fe3+ has been examined in terms of a catalytic regenerative mechanism. The catalytic currents due to homogeneous chemical reactionbetweenleucodyes and Fe3+ have been used to estimate rate constants.
[EN] METHODS OF CHEMICAL SYNTHESIS OF SUBSTITUTED 10H-PHENOTHIAZINE-3,7-DIAMINE COMPOUNDS<br/>[FR] PROCÉDÉS DE SYNTHÈSE CHIMIQUE DE COMPOSÉS SUBSTITUÉS DE 10H-PHÉNOTHIAZINE-3,7-DIAMINE
申请人:WISTA LAB LTD
公开号:WO2017013174A1
公开(公告)日:2017-01-26
The present invention pertains generally to the field of chemical synthesis, and more particularly to methods of chemical synthesis which include the step of preparing a substituted 10H-phenothiazine-3,7-diamine compound of Formula (1) by a step of selective alkylation by reductive amination, in which the corresponding unsubstituted diamine of Formula (4) is reacted with aldehyde/ketone, under reductive amination conditions. The present invention also relates to such methods which incorporate additional subsequent and/or preceding steps, for example, to prepare compounds of Formulae (2) and (3) from compounds of Formula (1), and to prepare compounds of Formula (4) from, for example, compounds of Formulae (5), (6), (7), (8), and (9). Compounds of Formula (1), Formula (2), and Formula (3) are useful, for example, in the treatment of diseases of protein aggregation, such as Alzheimer's disease.
[EN] METHODS OF CHEMICAL SYNTHESIS OF DIAMINOPHENOTHIAZINIUM COMPOUNDS INCLUDING METHYLTHIONINIUM CHLORIDE (MTC)<br/>[FR] PROCÉDÉS DE SYNTHÈSE CHIMIQUE DE COMPOSÉS DE DIAMINOPHÉNOTHIAZINIUM RENFERMANT DU CHLORURE DE MÉTHYLTHIONINIUM (MTC)
申请人:WISTA LAB LTD
公开号:WO2015052496A1
公开(公告)日:2015-04-16
Methods of synthesizing and purifying certain 3,7-diamino-phenothiazin-5-ium compounds (referred to herein as "diaminophenothiazinium compounds") including Methythioninium Chloride (MTC) (also known as Methylene Blue) are provided.