Ferricyanide oxidation of 1-substituted pentaphenylpyridinium salts. A novel route to 1-substituted 2,3,4,5-tetraphenylpyrroles

1989 ◽  
Vol 54 (1) ◽  
pp. 200-205 ◽  
Author(s):  
Stanislav Böhm ◽  
Hanuš Slavík ◽  
Josef Kuthan
Keyword(s):  
Alkaline Medium ◽  
Potassium Ferricyanide

Oxidation of 1-substituted 2,3,4,5,6-pentaphenylpyridinium salts Ia-Ij by potassium ferricyanide in an alkaline medium yields the corresponding 1-substituted 2,3,4,5-tetraphenylpyrroles in 68 to 76% yields. The selectivity of the reaction is discussed.

Oxidation of polysubstituted pyridinium salts

1982 ◽  
Vol 47 (5) ◽  
pp. 1494-1502 ◽  
Author(s):  
Petr Nesvadba ◽  
Josef Kuthan
Keyword(s):  
Alkaline Medium ◽  
Electrophilic Substitution ◽  
Pyridine Ring ◽  
Potassium Ferricyanide ◽  
Pyridinium Salts ◽  
Complex Reaction

Oxidation of 1-substituted 2,4,6-triphenylpyridinium salts Ia-Ij with potassium ferricyanide in an alkaline medium was accompanied by contraction of the pyridine ring and formation of 1,2,3,5-tetrasubstituted pyrroles II. The derivative IIf underwent facile electrophilic substitution in the position 4. Contrary to compounds Ia-Ij, the 1-substituted-2,6-diphenylpyridinium salts IIIa,b were oxidized to give a complex reaction mixture containing 4-pyridones IVa,b.

The oxidation of ortho-anisidine in alkaline medium. A product characterization and an EPR study

1994 ◽  
Vol 72 (5) ◽  
pp. 1351-1356 ◽  
Author(s):  
Adele Bolognese ◽  
Marina Buonanno ◽  
Antonio Cantilena ◽  
Giovanni Musci ◽  
Angelo Alberti
Keyword(s):  
Aqueous Solution ◽  
Alkaline Medium ◽  
Potassium Ferricyanide ◽  
Azo Compounds ◽  
Radical Mechanism ◽  
Radical Species ◽  
Alkaline Aqueous Solution ◽  
Product Characterization ◽  
Alkaline Oxidation

Alkaline oxidation of ortho-anisidine by potassium ferricyanide in alkaline aqueous solution was examined. Azo compounds, a diamine, and para-iminoquinones were isolated from the highly coloured reaction mixture. The reaction was also carried out within the cavity of an EPR spectrometer and two radical species have been detected. Following these product results and EPR studies, a radical mechanism is proposed for the process.

TEM comparison of osmium vs osmium with potassium ferricyanide secondary fixatives and the impact of secondary fixative temperature on tissue preservation/contrast quality

1996 ◽  
Vol 54 ◽  
pp. 910-911
Author(s):  
J. W. Horn ◽  
B. J. Dovey-Hartman ◽  
V. P. Meador
Keyword(s):  
Osmium Tetroxide ◽  
Potassium Ferricyanide ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Microscopic Evaluation ◽  
Cacodylate Buffer ◽  
Transmission Electron Microscopic ◽  
Glutaraldehyde Solution ◽  
Temperature Impact ◽  
The Impact

Osmium tetroxide (OsO4) is a universally used secondary fixative for routine transmission electron microscopic evaluation of biological specimens. Use of OsO4 results in good ultrastructural preservation and electron density but several factors, such as concentration, length of exposure, and temperature, impact overall results. Potassium ferricyanide, an additive used primarily in combination with OsO4, has mainly been used to enhance the contrast of lipids, glycogen, cell membranes, and membranous organelles. The purpose of this project was to compare the secondary fixative solutions, OsO4 vs. OsO4 with potassium ferricyanide, and secondary fixative temperature for determining which combination gives optimal ultrastructural fixation and enhanced organelle staining/contrast.Fresh rat liver samples were diced to ∼1 mm3 blocks, placed into porous processing capsules/baskets, preserved in buffered 2% formaldehyde/2.5% glutaraldehyde solution, and rinsed with 0.12 M cacodylate buffer (pH 7.2). Tissue processing capsules were separated (3 capsules/secondary fixative.solution) and secondarily fixed (table) for 90 minutes. Tissues were buffer rinsed, dehydrated with ascending concentrations of ethanol solutions, infiltrated, and embedded in epoxy resin.

Kinetics and Mechanism of Oxidation of Labetalol by Hexacyanoferrate(III) in Alkaline Medium

2012 ◽  
Vol 3 (2) ◽  
pp. 131-133
Author(s):  
ANNAPURNA NOWDURI ◽  
◽  
Apparao Babu Duggada ◽  
Vijaya Raju Kurimella
Keyword(s):  
Alkaline Medium ◽  
Kinetics And Mechanism ◽  
Mechanism Of Oxidation

Use of Low Pressure Mercury Lamps for the Photodecomposition of Iron Cyanide in Gold Mill Effluents

1985 ◽  
Vol 20 (2) ◽  
pp. 111-119 ◽  
Author(s):  
J.H. Carey ◽  
S.A. Zaidi
Keyword(s):  
Ultraviolet Light ◽  
High Intensity ◽  
Experimental Evaluation ◽  
Low Pressure ◽  
Pilot Scale ◽  
Weak Acid ◽  
Potassium Ferricyanide ◽  
Technical Feasibility ◽  
Iron Cyanide ◽  
Scale Test

Abstract The use of ultraviolet light (UV) from low pressure mercury lamps for destroying iron cyanide in synthetic and actual gold mill effluents was evaluated in this study. For the light intensities used in this study, UV irradiation was not able to efficiently destroy cyanide. However, it converted iron cyanide to a weak acid dissociable form which was destroyed by chlorine. Data from several bench-scale tests and one pilot scale test were used to estimate quantum efficiencies (moles iron cyanide destroyed/einstein). These efficiencies ranged from 0.2% to 1%; approximately 30% to 90% lower than those reported in the literature for potassium ferricyanide. The data collected during the study demonstrated the technical feasibility of using UV in conjunction with chlorination for destroying iron cyanide in gold mill effluents. However, low pressure mercury lamps do not appear to be a practical UV source for this purpose. Irradiation with high intensity lamps may be more practical and is recommended for experimental evaluation.

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