Phenoxazines

The parent lings are always included in phenazine [92-82-0] (4), phenoxazine [135-67-1] (5), oi phenothiazine [92-84-2] (6) ting systems. 

Additional examples have been reported (5). Disperse dyes which contain an oxazine ring include the yeUow 1,3-dinitro-lOhd-phenoxazine... 

Actinocin — see Phenoxazine-l,9-dicarboxylic acid, 2-amino-4,6-dimethyl-3-oxo-Actinoleutin applications, 3, 195 Actinomycins... 

Phenoxazine-1,9-dicarboxylie acid, 2-amino-4,6-dimethyI-3-oxo-occurrence, 3, 1037 Phenoxazines arylation, 3, 1011 electrophilic reactions, 3, 1012 nitration, 3, 1012 nomenclature, 3, 996 oxidation, 3, 1010 reactions, 3, 1011 structure, 2, 4, 7-8 3, 1010 synthesis, 3, 1033... 

Phenoxazin-3-ones synthesis, 3, 1034 Phehprocoumon H NMl 3, 582 Phensuximide as anticonvulsant, 1, 166 Phentolamine... 

Oxidation of P-nicotinamide adenine dinucleotide (NADH) to NAD+ has attracted much interest from the viewpoint of its role in biosensors reactions. It has been reported that several quinone derivatives and polymerized redox dyes, such as phenoxazine and phenothiazine derivatives, possess catalytic activities for the oxidation of NADH and have been used for dehydrogenase biosensors development [1, 2]. Flavins (contain in chemical structure isoalloxazine ring) are the prosthetic groups responsible for NAD+/NADH conversion in the active sites of some dehydrogenase enzymes. Upon the electropolymerization of flavin derivatives, the effective catalysts of NAD+/NADH regeneration, which mimic the NADH-dehydrogenase activity, would be synthesized [3]. 

Chromoionophore I [ETH 5294] [9-diethylamino-5-octadecanoyl-imino-5-//-benzo[a]-phenoxazine] [125829-24-5] M 583.9. Purified by flash chromatography (Silica Gel) and eluted with EtOAc. The coloured fractions are pooled, evaporated and recrystd from EtOAc. It is a lipophilic chromoionophore and is a selectophore for K and Ca ions. [Anal Chem 62 738 7990.]... 

Resorufin (7-hydroxy-3H-phenoxazine-3-one Na salt) [635-78-9] M 213.2, pK 6.93, pKj 9.26, pK l0.0. Washed with water and recrystd from EtOH several times. 

Amino-4,6-dimethyl-3-oxo-3//-phenoxazine-l,9-dicarboxylic acid also named actinocin is the chromophor of the red antineoplastic chromopeptide aetinomyein D (formula A). Two cyclopenta-peptide lactone rings (amino acids L-threonine, D-valine, L-proline, sarcosine, and 7V-methyl-L-valine) are attached to the carboxy carbons of actinocin by two amide bonds involving the amino groups of threonine. 

Phenoxazine analogues 270 were prepared by thermolysis of azides 269 in decalin in 43-72% yields (Scheme 175) (96UP1). 

Porphyrins, modified natural chlorophylls, chlorins, phthalocyanins, xanthenes, phenothiazine, and phenoxazine dyes as new sensitizers for photodynamic therapy 98MI50, 98MI51, 98MI52, 98MI53. 

Aromatic denitrocyclizations have been used for many years in some well-known synthetic reactions. Probably the best known example is the Turpin synthesis of phenoxazines and similar synthesis of phenothiazines. The classical setup used usually base-catalyzed reactions in polar protic solvents, very often alcohols. In many cases using polar aprotic solvents was found advantageous. Besides the mentioned influence of the H-bonding, better ionization and lower solvation of the nucleophile are also important. Sf Ar reactions proceed through strongly polarized complexes, which are well soluble and highly polarized in polar aprotic solvents. 

The best-known example of the denitrocyclization reactions is probably the Turpin synthesis of phenoxazines 179 (1891JCS714, 1899CB2601,... 

Treatment of 2-amino-3-hydroxypyridine (185) with 2-chloro-3-nitropyridine (193) easily provided intermediate 194. Attempts to cyclize 194 with potassium hydroxide in aqueous ethanolic solutions failed, probably due to strong H-bonding. Similarly as with phenoxazines, the cyclization smoothly proceeded in DMSO to give low yield (31%) of 1,9-diazaphenoxazine (195) (Scheme 30) (74CC878, 76JHC107, 77H391). 

Intramolecular cyclization can yield fluorinated phenoxazines by a Smiles rearrangement (86IZV1855) and 2,3-dihydro-l,4-benzodioxins by a base-induced reaction [81JFC(18)483]. 

Direct bromination of phenoxazine (103 X = O) gave rise to a mixture of 3-bromo- and 3,7-dibromo-phenoxazine. Reaction with thionyl chloride gave the 1,3,7,9-tetrachloro derivative (60JGU1872). 

NADH. Immobilized redox mediators, such as the phenoxazine Meldola Blue or phenothiazine compoimds, have been particularly useful for this purpose (20) (see also Figure 4-12). Such mediation should be useful for many other dehydrogenase-based biosensors. High sensitivity and speed are indicated from the flow-injection response of Figure 3-21. The challenges of NADH detection and the development of dehydrogenase biosensors have been reviewed (21). Alcohol biosensing can also be accomplished in the presence of alcohol oxidase, based on measurements of the liberated peroxide product. 

CN stereoisomer of /V,iV-[(2-amino-4,6-dimethyl-3-oxo-377-phenoxazine-l,9-diyl)bis[carbonylimino[2-( 1 -hydroxyethyl)-1 -oxo-2,1 -ethanediyl]imino[2-( 1 -methylethyl)-1 -oxo-2,1 -ethanediy 1]-1,2-pyrrolidinediylcarbonyl(methylimino)(l-oxo-2,l-ethanediyl)]]bis[A/-methyl-L-valine] di- -lactone... 

Phenoxazines — A phenoxazine has a ring skeleton that differs from phenazine by the fact that the nitrogen at position 5 is replaced by an oxygen atom. ... 

Phenoxazines — The two main types of phenoxazines are the ommochromes and the microbial phenoxazines. The biosynthesis of ommochromes occurs via the kynurenine pathway. The tryptophan amino acid is converted to formylkynurenine and then to kynurenine and 3-hydroxykynurenine. Not all the steps of ommochrome synthesis are completely elucidated yet. Ommatins are dimers and ommins are oligomers of 3-hydroxykynurenine. - The papiliochromes are derived from tyrosine as well as from the tryptophan pathway. The key intermediate in the formation of papiliochromes is N-beta-alanyldopamine (NBAD). Papiliochromes are synthesized in special wing scale cells, before melanins. " "... 

Phenoxazines — The microbial phenoxazines like actinomycins are well-known antibiotics. Actinomycin D produced by Streptomyces anibioticus is an effective antineoplastic agent that inhibits nucleic acid synthesis. The main function of ommochromes is to act as screening pigments in the eyes of insects and other arthropods, as pattern pigments in the integument, and as excretion products of excess tryptophan. ... 

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