2,7-Phenanthrenequinones, from

Phenanthrenequinone from benzoin. The photocyclization of stilbene to phenanthrene requires a trans to cis isomerization. This step can be circumvented by reaction of benzoin with phenylboric acid to form the 1,3-dioxoborole 2. This adduct can be converted to phenanthrenequinone by photocyclization in the presence of diphenyl diselenide as the oxidant. 

Isocyanates 345 react with phenanthrenequinone 346 and triphenylarsine oxide to give photochromic oxazines 347 (Equation 48) <1993PS(81)37>. The isocyanate can be replaced by a phosphinimine and the phenanthrene structure can also be replaced by the corresponding phenanthroline (Equation 49) <2003WO42195>. The /ra r-fused tetrahydrooxazine 349 was prepared from epoxide 348 and 2-aminoethyl sulfate (ethanolamine 0-sulfonic acid) (Equation 50) <1987AP625>. 

The solid state photochemical reaction of indole with 1,4-naphthoquinone yielded 5H-dinaphtho(2,3-a 2, 3 -c)carbazole-6,ll,12,17-tetrone in addition to 2-(3-indolyl)-1,4-naphthoquinone which was also the only product in the solution photoreaction. Solventless thermochemical reactions of indole with phenanthrenequinone in the presence or absence of zinc chloride gave 10-(lH-indol-3-yl)-9-phenanthrenol and 9,10-dihydro-9-(lH-indol-3-yl)-10-(3H-indol-3-ylidene)-9-phenanthrenol or 10,10-di-lH-indol-3-yl-9(10H)-phenanthrenone, respectively. All of these products were only obtained in trace amounts in corresponding solution reactions, and are different from the adduct 10-hydroxy-10-(lH-indol-3-yl)-9(10H)-phenanthrenone obtained in the solution photoreaction (Wang et al., 1998). 

Phenanthrenequinone has been prepared by treatment of phe-nanthrene with chromic acid in acetic acid 5 potassium dichromate in sulfuric acid 3-6 hydrogen peroxide in acetic acid 6 7 and selenium dioxide above 250°.8 It can also be prepared from benzil with aluminum chloride at 120° 9 and from biphenyl-2,2 -dialdehyde with potassium cyanide.10... 

Phenanthrenequinone free of anthraquinone is available from Aldrich Chemical Company, Inc., or from J. T. Baker Chemical Company. It should be recrystallized from benzene before use. 

Cooke and coworkers have reported preparation of flavin-modified electrodes using a similar electropolymerization procedure.34 They have also studied electrodes coated with self-assembled monolayers (SAMs) formed from both flavin39 and phenanthrenequinone disulfides.59 The monolayers are stable in CH2C12 solution, and, as with the electrodes formed from 30, show redox-dependent binding behavior similar to that seen in solution. Interestingly, the phenanthrenequinone SAM... 

The phenanthrenequinone oxime 54 was built in four steps from the two benzenoid precursors 52 and 53. Beckmann rearrangement of 54 furnished the cyano-acid 55. The latter, after reduction to the corresponding cyano-aldehyde, was homologated by Knoevenagel condensation with malonic acid to give, after reduction, hydrolysis and esterification, the diester 56. This compound underwent Dieckmann condensation, installing the seven-membered C-7 ketone 57 in 69% yield after hydrolysis and decarboxylation of the intermediate (3-ketoester. 

Estimates of the triplet energy level of a molecule may be made by observing whether it can accept or transfer energy to several other molecules. Hammond and co-workers42 have shown that ds-trans interconversions of piperylene, 2-pentene, and 1 2 dichloroethylene may be affected by many photosensitizers. The stationary states of the sensitized ds-trans ratios of piperylene with various donors were found to form a coherent pattern if triplet energy transfer was assumed as the key step in the photochemical reaction. From these results they were able to infer the presence and the energies of the triplet states of acetone, phenanthrenequinone, and fluorenone, for which phosphorescence data are not available. The triplet levels were estimated as >70, 65, and 62 kcal./mole, respectively. 

Phenanthro[9,10-c]-l,2,5-tclluradiazole 1,1-dichloride3 9,10-Bis-[trimethylsilylimino]-9,l0-dihydrophenan-threne is prepared from 9,10-phenanthrenequinone and sodium bis[trimethylsilyl]amide. A solution of 405 mg (1.5 mmol) of tellurium tetrachloride in 10 ml absolute toluene is dropped at 20° to a solution of 520 mg (2.48 mmol) of 9,10-bis[trimethylsilylimino]-9,10-dihydrophenanthrene in 29 ml absolute toluene. The mixture is stirred for 1 h. The orange-red precipitate is collected by filtration yield 85% m.p. 240° (dec.). 

A. 9,10-Dimethoxyphenanthrene. A mixture of 26 g (0.125 mol) of 9,10-phenanthrenequinone (Note 1), 13 g (0.04 mol) of tetrabutylammonium bromide (Bu NBr), 65 g (0.37 mol) of sodium dithionite (Na2S204), 250 mL of tetrahydrofuran (THF), and 250 mL of water is shaken for 5 min in a 2-L separatory fiinnel. Dimethyl sulfate (62 mL, 0.65 mol) is added, followed by an aqueous solution of sodium hydroxide (64 g, 1.6 mol, in 125 mL of water) and 200 g of ice. The mixture is shaken for 5 min and, after another 200 g of ice has been added, shaken for another 10 min. Ethyl acetate (EtOAc, 100 mL) is added and the mixture is shaken. The aqueous phase is separated and extracted with EtOAc (2 x 100 mL). The combined organic extracts are washed with water (3 x 100 mL), 15% aqueous ammonia (2 X 100 mL), water (3 x 100 mL), and finally brine (100 mL). The solution is dried over sodium sulfate (Na2S04) and filtered. The solvents are removed under vacuum (initially using a water aspirator, then at 0.5 torr). The residue, a thick brown oil. is dissolved in 80 mL of a ca. 2 1 mixture of dichloromethane (CH2CI2) and hexane and poured onto a plug of neutral alumina, from which it is eluted with a 170-mL portion of the solvent mixture. After the solvent has been removed, the residue is dried under vacuum (ca. 0.5 torr) to give 23.7 g (80%) of 9,10-dimethoxyphenanthrene as a yellow oil (Note 2). 

Phenanthrenequinone (95%), purchased from Acros, was used as received. The checkers purchased it from Tokyo Chemical Industry. 

Major groove intercalators bind DNA with high affinity (Ka > 10 M- )and, in some cases, high sequence specificity. Indeed, an extended aromatic system on the ligand outward from the metal center, as in the case of the phi (9,10-phenanthrenequinone... 

This compound is formed by melting phenanthrene-naphthazine-sulphonie acid (from phenanthrenequinone and a -naphthylene-diaminesulphonic acid) with caustic potash. It dissolves in concentrated sulphuric acid with a blue colour, which suddenly changes into bright red on dilution. Its sulphonic acid is a yellow dyestuff. 

Tamarkin, D., Rabinovitz, M. Hyper-acyloin condensation from simple aromatic esters to phenanthrenequinones a new reaction of CsK. J. 

Substituted orthoquiiutnes. Crude phenanthrenequinone prepared by oxidation of technical (90%) phenanthrene can be freed from anthraquinone and other contaminants by triturating it with 4-6 portions of hot 40% bisulfite solution, filtering, cooling, collecting the adduct, and adding hydrochloric acid to a suspension in water."... 

Purification. Yields reported are not strictly comparable because of variations in the purity of the phenanthrene used, particularly with respect to the content of anthracene. Crude phenanthrenequinone can be separated easily from anthra-quinone and >thcr impurities through the water-soluble bisullile addition compound. - Thus a simple mule to pure qtiinonc at moderate cost is by bisullile piirillcalion of the 80% technical malcriiil. 

The necessity of the presence of H2O molecules, has been traced to their dipole moment, easing the proton abstraction from the weak quinhydrone acid (a). The adsorption on the surface should stabilize the two ion radicals (c), which are unstable in alkaline solutions. Similar results were obtained with the addition compounds thymoquinone-hydroquinone, phenanthrenequinone-hydroquinone, giving blue-green coloration and likewise EPR single lines. It is important to note that phenanthrenequinone alone, without association with a hydroquinone could produce similar effects, i.e., could evidently form an adsorbed anion. 

An alternative scheme was proposed by Moore and Waters 10°) to account for the high yield obtained in the reaction of benzaldehyde with phenanthrenequinone. They suggested that the initially formed radical R adds to a ground-state quinone molecule to give a new radical which then abstracts hydrogen from RH to regenerate the radical R ... 

There is evidence that some of these reactions may be photochemically reversible. Thus, irradiation of the adduct of phenanthrenequinone and dioxane in benzene solution led to a mixture having approximately the same composition as that obtained from irradiation of dioxane and the quinone 128>. Irradiation 133> of the adducts of this quinone with benz-aldehyde or -xylene also resulted in regeneration of quinone. 

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