Containing Phenazines

Phenazines — These are dibenzopyrazine derivatives with fnnctional groups (hydroxy-, carboxy-) at C, and Cg and an oxygen or methyl gronp at Nj and N,o. There are also more complex structures, substituted phenazines, terpenoidal, and carbohydrate-containing phenazines and phenazines derived from saphenic acid. ... 

Aniline black is also an important fast dye for cotton and is produced on the fibre at a high temperature (by steaming ) from an aniline salt (hydrochloride) and an oxidising agent. It is not probable that the two kinds of this dye which are known have the same constitution, for they have different degrees of stability towards acid technical aniline black probably contains phenazine ring systems (Bucherer, Green). 

Basic azines are predominantly of historical interest. Yellow, red, brown, blue, and black shades can be obtained with these dyes. Today, Nigrosine Spirit Soluble is still used in shoe polish and creme. The sulfonated variety is applied as a leather dye. It is a polymeric dye containing phenazine ring systems, similar to Aniline Black. C.I. SolventBlack 5, 50415 [11099-03-9] (Nigrosine, spirit-soluble) C.I. Solvent Black 7, 50415 1 [8005-02-5] (4) is the free base. 

Hexokinase procedures in which indicator reactions produce colored products are also available, enabling absorbance to be measured in the visible range. An oxidation-reduction system containing phenazine methosulfate (PMS) and a substituted tetrazolium compound, 2-(p-iodophenyl)-3-p-nitrophenyl-5-phenyltetrazolium chloride (INT), is reacted with NADPH formed in the reaction. The reduced INT is colored with maximum absorbance at 520 nm. The PMS-INT color developer must be refrigerated... 

Visual localization of electrophoretically separated LDH isoenzymes is accomplished by the reduction of nitro-tetrazolium blue as the electron acceptor (terminal) in a medium containing phenazine methosulfate and NAD. The linked reaction is as follows ... 

P2ADPA contains phenazine and open-ring (PANI-like) units. 

Carbohydrate-containing phenazine natural products are rare, and only a few examples exist, all... 

Figure 5. Carbohydrate-containing phenazines isolated from Streptomyces sp.

Scarcely a single issue of Chemical Abstracts is published without reference to medicinal compounds containing the pyrazine or quinoxaline ring in some form, and hence it is impractical to list all applications of pyrazines, quinoxalines and phenazines. Some of the more important applications and natural products, particularly the more recent developments, are mentioned in this Section. 

Historically the phenazine dyes have played an important part in the dyestuffs industry, although their use has largely been superseded by the more modern, color-fast dyes, in particular those dyes which become chemically bonded to the fibers of the materials being dyed. Amongst the earliest examples of phenazine dyes are those compounds known as the safranines. The discovery of the safranines has been attributed to Greville Williams in 1859 and they were apparently in commercial use shortly after that date, but it was not until 1886 that it was recognized that phenosafranine (138) was indeed a phenazine containing system. 

Methyl coenzyme M reductase plays a key role in the production of methane in archaea. It catalyzes the reduction of methyl-coenzyme M with coenzyme B to produce methane and the heterodisulfide (Figure 3.35). The enzyme is an a2P2Y2 hexamer, embedded between two molecules of the nickel-porphinoid F jg and the reaction sequence has been delineated (Ermler et al. 1997). The heterodisulfide is reduced to the sulfides HS-CoB and HS-CoM by a reductase that has been characterized in Methanosarcina thermoph-ila, and involves low-potential hemes, [Fe4S4] clusters, and a membrane-bound metha-nophenazine that contains an isoprenoid chain linked by an ether bond to phenazine (Murakami et al. 2001). 

The oxidation of N ADH has been mediated with chemically modified electrodes whose surface contains synthetic electron transfer mediators. The reduced form of the mediator is detected as it is recycled electrochemically. Systems based on quinones 173-175) dopamine chloranil 3-P-napthoyl-Nile Blue phenazine metho-sulphatemeldola blue and similar phenoxazineshave been described. Conducting salt electrodes consisting of the radical salt of 7,7,8,8-trtra-cyanoquinodimethane and the N-methylphenazium ion have been reported to show catalytic effects The main drawback to this approach is the limited stability... 

A recently characterized class of dehydrogenases are the quinoproteins which contain a pyrroloquinolene quinone prosthetic group and do not require a separate co-factor Electron transfer mediators such as phenazine ethosulphate 2,6-dichloroindophenol and ferricenium ions have been used to recycle the quinoprotein the reduce mediator is detected amperometrically. 

Needless to say, the Buchwald-Hartwig reaction can also be usefully employed in ways other than the efficient preparation of diphenylamines. Given the respective substitution, it should be possible to bring about the phenazine skeleton by Pd-catalyzed ring formation as well. There are two ways to proceed either the substituent pattern required by the intramolecular Buchwald-Hartwig reaction is elaborated after the formation of the diphenylamine (121 124), or the starting material already contains the substituents necessary for the two JV-arylations. A reasonable starting point is the intermolecular JV-arylation of an o-haloaniline... 

Larson et al. (1992) studied the photosensitizing ability of 2, 3, 4, 5 -tetraacetylriboflavin to various organic compounds. An aqueous solution containing aniline was subjected to a medium-pressure mercury arc lamp (X >290 nm). The investigators reported that 2, 3, 4, 5 -tetraacetylribofiavin was superior to another photosensitizer, namely riboflavin, in degrading aniline. Direct photolysis of aniline without any photosensitizer present resulted in a half-life of 23 h. In the presence of riboflavin and 2, 3, 4, 5 -tetraacetylribofiavin, the half-lives were 1 min and 45 sec, respectively. Photoproducts identified in both reactions were azobenzene, phenazine, and azoxybenzene. 

The preparation and structure of [Ru(phen)2(l,5,6,10-tetraazaphenanthrene)]Cl2 have been reported NMR spectroscopic data provide insight into the hydrophilic properties of the complex. The bpy-containing complexes [Ru(bpy)2(92)] + and [ Ru(bpy)2 2(M 92)] ((92) = dipyrido(2,3-a 2, 3"-/z)phenazine) were described earlier in the chapter.The analogous [Ru(phen)2(92)] and [ Ru(phen)2 2(M 92)]" have also been prepared and characterized, as has [ (phen)2Ru(/i-92) 3Ru] +. The electronic spectra exhibit intense MLCT bands in the visible region the electrochemical properties of the complexes have been investigated and for [ (phen)2Ru(/i-92) 3Ru], two sets of reduction waves centered on ligand (92) are separated by those assigned to phen reductions. ... 

Rapid and sensitive HPLC methods were developed for the detection of an antimicrobial growth promoter and its main metabolites containing quinoxaline-2-carboxylic acid <2005MI1495>. The major phenazine pigments of Pseudomonas aeruginosa such as 1-hydroxyphenazine and phenazine-l-carboxylic acid <1997JCH(A)(771)99>, and 2-aminophenazine as an impurity in a bactericide <1999MI632>, were also analyzed by HPLC methods. 

A poly(phenylquinoxaline) was prepared for electroluminescence applications <1996SM(76)105>. Crystallization of solution donor-acceptor complexes of 2,3-dimethylquinoxaline 1,4-dioxide or phenazine 5,10-dioxide with TCNE afforded two-component solids containing weakly bound 1-D donor-acceptor arrays <1997TL7665>. A pyrazine ladder polymer was constructed from two different pyrazine units, as an optical device <1999JA8783>. The new electron-deficient macrocycle tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazine was prepared from l,2-di(2-pyridyl)ethanedione and 2,3-diaminomaleonitrile for a study of its electrochemical properties <2004IC8626>. 

RCHO - RCOOCHy. This salt, in CH,OH containing N(C2H5)3, catalyzes a Mdox reaction in which aldehydes are oxidized to methyl esters, and certain organic Compounds such us acridine (2) and phenazine are reduced, lixamplcs ... 

Anodic oxidation of 4 -substituted 2-nitrobenzenesulfenanilide in CH3CN-ethyltributylammonium trifluoromethanesulfonate, containing 1% trifluoro-acetic acid and 1% trifluoroacetic anhydride, is reported to give 2,7-disubsti-tuted phenazines in 24-56% yield.113... 

Positively charging CCAs are organic molecules with a positive charge. Colored positive CCAs tend to be the black Nigrosine dyes, which are mixtures of compounds in which highly arylated phenazines (8) are the major component. Colorless positive CCAs tend to contain a quaternary nitrogen atom cetylpyridi-nium chloride (9), also found in antiseptic mouthwashes, is one of the most widely used [2,3], Triphenylmethane, benzimidazolium and beta di- and tri-car-bonyl compounds are also used [6],... 

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