Phenoxazines from

Phenoxazine [135-67-1] M 199.2, m 156", 156-158", 158-159", b 215"/4mm. Crystallise phenoxazine from EtOH and sublime it in vacuo. If too impure then extract it in a Soxhlet extractor using... 

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. 

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. 

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. " "... 

The blue dye (47), formed from the autoxidation of 4-/V,TV-di methyl-amino-2-hydroxyaniline, is the oxygen analogue of methylene blue. The autoxidation of 1,2,4-trihydroxybenzene, carried out in the presence of ammonia, gives the hydroxyphenoxazinone dye (48) via a 2,4-dihydroxyani-line intermediate (Scheme 17). Many types of phenoxazines, phenazines, and phenoxazinium salts can be obtained by autoxidation of polyhydroxyben-zenes and their amino derivatives. Some autoxidative dyes may give poly-... 

Examples of nonacylated oxazine leucos are rare, possibly due to the high cost of the phenoxazine starting material. Apart from a few examples described earlier, the leuco 35 is reported to give a blue image.8... 

Starting from phenoxazine, the leuco 47 is obtained through a multistep reaction involving nitration, reduction, and acylation.6... 

Synthetic Method 7 l,9-dimethyl-4-acetarnido-8-diethylaminoimidazo-phenoxazine (31) (procedure from U.S. Patent 4,604,462). 12 A mixture of 10 g of l,3-diamino-7-diethylamino-8-methylphenoxazin-5-ium chloride (Brilliant Cresyl Blue), 50 ml of acetic anhydride, 10 g of zinc dust, and 10 ml of pyridine was maintained at 85 to 90°C for approximately 1 h. After cooling to room temperature, the reaction mixture was poured into a mixture of water and toluene and the resulting aqueous layer was discarded. The toluene solution was washed twice, first with water and then with... 

Another way of getting around the problem of the separation of the catalyst from the substrate is via use of a flow reactor [38], Supercritical carbon dioxide has been used successfully as a medium for the hydroformylation of 1-octene using an immobilized rhodium catalyst. The catalyst is covalently fixed to silica through the modifying ligand A-(3-trimethoxysilyl-n-propyl)-4,5-bis(diphenylphosphino)phenoxazine (Figure 8.13). Selectivity was found to be... 

A group at Lilly reported that phenoxazine (89) is a potent inhibitor of cRBL (0.02 iM) [237]. Substitution at the 1-position by carboxylic acid, ester, or hydroxamic acid groups decreased potency 10- to 30-fold. Substitution at the 2-position was less destructive of inhibition as long as the substituent was lipophilic (ester, acrylate ester) carboxylate caused a 200-fold loss of potency. Activity in rat neutrophils has been disclosed for related structures in patents from Bayer [238]. The second aromatic ring is not required, as shown by the activity of series exemplified by (90)-(92) [239-242]. Antiasthmatic activity was indicated for these compounds, but few details were given. 

The rhodium complex with bis(diphenylphosphino)phenoxazine was immobilized on silica using the sol-gel technique or by a direct grafting to commercially available silica [127]. Under standard hydroformylation conditions (CO/H2 atmosphere), a neutral hydridic complex (57) and cationic species (58) (Scheme 4.35) coexist on the support and act as a hydroformylation/hydrogenation sequence catalyst, giving selectively 1-nonanol from 1-octene 98% of 1-octene were converted to mainly linear nonanal which was subsequently hydrogenated to 1-nonanol. The... 

Dactinomycin Dactinomycin, 2-amino-l,9-bis-(2,9-diisopropyl-6,10,13-trimethyl-l,4,8,ll,14-pentaoxo-7-oxa-3,10,13-17a-tetraaza-5-bicyclo[14.3.0]nonadecylcarbamoyl)-4,6-dimethyl-3//-phenoxazin-3-one (30.3.1), is one of the first antibiotics isolated from a liquid culture of microorganisms of the family Streptomyces parvulus [80-87]. It is a chromonopeptide with a phenoxazine ring and two cyclic polypeptides joined to the carboxyl group at position 2 and 9 of the phenoxazine ring. 

Phenoxazin-3-ones and phenothiazin-3-ones can be prepared by condensation of 2-aminophenols or -thiols with quinones. Alizarin Green G (61), for example, is obtained from (59) and (60). Similarly, 2-aminothiophenols and 6-chloro-2-methoxy-l,4-benzoquinone (62) afford phenothiazin-3-ones (63). 

It seems likely that aromatic amines which are found in liquefaction products have been produced by a combination of thermolysis and hydrogenation. There is no evidence for aromatic amines in coals from either selective oxidation degradations (22) or from direct X-ray Photoelectron Spectroscopy measurements (23). Oxidations would produce very stable nitroaromatics which are not seen. Another possible structure for this formula is phenoxazine(Vb). Such a molecule would not survive high temperature combined with long reaction times. Although annelated thiophene with a pyrrole(VI) would appear to be a likely structure in coal, there is no evidence for its existence in any of the coal derived materials. 

The phenoxazine-based ligand Nixantphos 8, which was derived from van Leeuwen s initial studies of xanthene-based diphosphine ligands [36], was used as the catalyst in a hydroformylation reaction as well. Nixantphos 8 proved to be a superior ligand with regard to its selectivity towards the linear aldehyde [37]. Moreover, Nixantphos 8 has recently been successfully immobilized on a silica 9 [38-40] and polystyrene 10 [41] matrix. After metal complexation, a catalyst can be obtained that is suitable for recycling by simple filtration (Fig. 4). 

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