- Electrolysis at an Anthracene Crystal/Aqueous NO3- Solution Interface: The Role of Crystal Defects
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The electrolysis of a 1 M solution of NaNO3 by means of an anthracene crystal electrode results in the production of many surface reaction products, including 9-nitroanthracene (9NA), bianthronyl (BA), and anthraquinone (AQ).The production of 9NA and BA have been shown to depend on the square of the current density.This dependence was rationalized by hypothesizing the need for the simultaneous discharge of two carriers at adjoining lattice defect sites.By annealing the crystals, it was found that the efficiency of producing 9NA was reduced by a factor of as much as 6; this supports the hypothesis.
- Pope, M.,Mao, B.,Steigman, J.,Geacintov, N. E.
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- Photophysics and Photochemistry of Nitroanthracenes. Part 2. Primary Process in the Photochemical Reaction of 9-Nitroanthracene studied by Steady-state Photolysis and Laser Photolysis
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From measurements of phosphorescence and triplet-triplet absorption spectra of the lowest excited triplet ??* state of 9-nitroanthracene (NA) together with the absorption spectrum of 9-anthryloxy radical, it is concluded that photolysis of 9-nitroanthracene gives rise to the nitro -> nitrite rearrangement for a higher excited triplet state of n?* character, followed by the cleavage of 9-anthryl nitrite to 9-anthryloxy radical and nitrogen(II) oxide, yielding 9-anthrol (and anthrone), 10,10'-bianthrone and 9-nitrosoanthrone in ethanol; and 10,10'-bianthrone and 9-nitrosoanthrone in benzene.Hence, the primary process in the photochemical reaction of NA is essentially identical with those of 9-benzoyl-10-nitroanthracene and 9-cyano-10-nitroanthracene except that no 10,10'-bianthrone derivatives are formed.
- Hamanoue, Kumao,Nakayama, Toshihiro,Kajiwara, Kanji,Yamanaka, Shigenobu,Ushida, Kiminori
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- Direct Exploitation of the Ethynyl Moiety in Calcium Carbide Through Sealed Ball Milling
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Ball milling of calcium carbide (CaC2) enables the reaction of its ethynyl moiety with organic electrophiles. This was realized simply by co-milling CaC2 with organic substrates in a sealed jar without the need for an additive or a catalyst. Various ketones including those bearing α-hydrogens were ethynylated in good yields at short reaction times. Aryl halides are also amenable substrates for this protocol as they furnish aryl ethynes through a benzyne intermediate. This method offers a practical and cheap alternative to the established procedures for introducing ethynyl functionalities.
- Hosseini, Abolfazl,Schreiner, Peter R.
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p. 4339 - 4346
(2020/07/04)
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- Oxidation of benzyl alcohols, benzyl halides, and alkylbenzenes with oxone
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Oxidation of benzyl alcohols, benzyl halides, and alkylbenzenes to their corresponding oxidation products has been shown to be accomplished directly with oxone. The methodology that involves mere stirring/heating of the reactants and oxone in acetonitrile/water (1:1, v/v) is simple and practical, but is limited to substrates that do not contain sensitive functionalities and heteroaromatic rings.
- Parida, Keshaba Nanda,Jhulki, Samik,Mandal, Susovan,Moorthy, Jarugu Narasimha
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p. 9763 - 9768,6
(2020/08/20)
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- Oxidative-substitution reactions of polycyclic aromatic hydrocarbons with iodine(III) sulfonate reagents
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Polycyclic aromatic hydrocarbons (PAH) undergo regioselective oxidative-substitution reactions with iodine(III) sulfonate reagents in dichloromethane to give the corresponding aryl sulfonate esters. The use of [hydroxy(tosyloxy)iodo]benzene in conjunction
- Koser, Gerald F.,Telu, Sanjay,Laali, Kenneth K.
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p. 7011 - 7015
(2007/10/03)
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- Efficient pyridinylmethyl functionalization: Synthesis of 10,10-bis[(2-fluoro-4-pyridinyl)methyl]-9(10H)-anthracenone (DMP 543), an acetylcholine release enhancing agent
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2-Fluoro-4-methylpyridine (3) is efficiently functionalized by chlorination, hydrolysis and methane-sulfonylation into the novel alkylating agent 7. This mesylate is used for the bisalkylation of anthrone under carefully defined conditions to prepare the cognition enhancer drug candidate 1. This process proceeds in up to 37% overall yield and is adaptable for large scale synthesis.
- Pesti,Huhn,Yin,Xing,Fortunak,Earl
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p. 7718 - 7722
(2007/10/03)
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- Sc(OTf)3- and TfOH-catalyzed baeyer-villiger oxidation of carbonyl compounds with m-chloroperbenzoic acid
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An efficient method for Baeyer-Villiger oxidation of carbonyl compounds to the. corresponding esters/lactones has been developed using m-chloroperbenzoic acid in the presence of a catalytic amount of Sc(OTf)3 or TfOH. Thieme Stuttgart.
- Kotsuki, Hiyoshizo,Arimura, Koji,Araki, Tomohiro,Shinohara, Toshio
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p. 462 - 464
(2007/10/03)
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- Competition between nucleophilic addition and electron-transfer process in the reaction of 9-diazo-10-anthrone with Grignard reagents
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9-diazo-10-anthrone reacts with RMgX (R = Me, Et, Bu(n), 5-hexenyl, Pr(i), benzyl, Bu(t)) essentially yielding 9-alkylazo-10-hydroxy derivatives, which are isolated in their tautomeric quinoid structure as alkylhydrazones of 9,10-anthraquinone. The yields of these compounds decrease as the oxidation potentials (E(OX) of the Grignards decrease: at the same time additional compounds, formed through a radical mechanism, are obtained in higher yields. The reaction has been interpreted as a competition between single electron transfer (SET) and nucleophilic attack, which occur with ratios varying with the oxidation potentials of the Grignard reagents. Evidences for the SET pathway have been found performing an experiment in the presence of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as a scavenger of C-centered radicals.
- Bruni, Paolo,Carloni, Patricia,Conti, Carla,Giorgini, Elisabetta,Greci, Lucedio,Iacussi, Marco,Stipa, Pierluigi,Tosi, Giorgio
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p. 6795 - 6802
(2007/10/03)
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- THE SELECTIVE FUNCTIONALIZATION OF SATURATED HYDROCARBONS. PART 28. THE ACTIVATION OF BENZYLIC METHYLENE GROUPS UNDER GOAGGIV AND GOAGGV CONDITIONS
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Under GoAggIV and GoAggV conditions, cyclohexadienes were oxidized to give aromatic products instead of ketones and alcohols.At the same time, anthracene was oxidized to give anthraquinone.Under GoAggIV and GoAggV conditions, xanthene, fluorene and diphenylmethane were oxidized to give the corresponding xanthone, fluorenone and benzophenone following two possible pathways: a) alkane to alkyl t-butylperoxide to ketone, and b) alkane to ketone, in which alkyl hydroperoxide, derived from oxygen, may be the reaction intermediate.Xanthyl azide was formed when sodium azide was added to the reaction mixture of xanthene under GoAggIV and GoAggV conditions.The reaction of triphenylmethane under GoAggV conditions gave triphenylmethyl t-butyl peroxide as the major product and hydroperoxide as the minor product.When TEMPO was added, triphenylmethyl hydroperoxide was the only product.
- Barton, Derek H. R.,Wang, Tie-Lin
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p. 1011 - 1032
(2007/10/02)
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- Oxidation of arenes to para-quinones with hydrogen peroxide catalyzed by hexafluoroacetone hydrate
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Various aromatic hydrocarbons were oxidized with aqueous hydrogen peroxide in the presence of hexafluoroacetone hydrate as catalyst to give para-quinones and/or the ring cleavage oxidation products. The regioselective oxidation of 2-methylnaphthalene to 2-methyl-1,4-naphthoquinone (vitamin K3) was studied in detail.
- Adam,Ganeshpure
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p. 280 - 282
(2007/10/02)
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- Studies on the Formation of Benzanthrones in Alkaline Anthraquinone Pulping
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Loss of anthraquinone (AQ) in alkaline pulping is partly attributed to irreversible reactions of AQ or AQ-derived compounds with lignin fragments. 3-(4-Hydroxy-3-methoxyphenyl)benzanthracen-7-one, 3-(4-hydroxy-3,5-diemethoxyphenyl)benzanthracen-7-one and 3-(4-hydroxyphenyl)benzanthracen-7-one have been synthesized and their formation in reactions of isolated lignins has been studied. 2-(4-Hydroxy-3-methoxyphenyl)anthracene-9,10-dione (2-vanillylanthraquinone) has also been prepared.
- Karhunen, Pirkko,Brunow, Goesta
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p. 945 - 948
(2007/10/02)
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- On the Reaction between Anthracene and the Nitrosonium Ion. A Simple Method for the Preparation of 9,10-Anthraquinone and Some Comments on its Formation in Aromatic Nitration
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A summary of the possible electron-transfer reactions between anthracene and the nitrosonium ion, and a convenient and simple method for the synthesis of 9,10-anthraquinone from anthracene, NaNO2 and CH3OH in CH2Cl2/CF3COOH are presented.The suggestion that the formation of 9,10-anthraquinone in the N2O4 nitration of anthracene originates from trapping of the anthracene radical cation by water is demonstrated to be invalid, e.g., by experiments involving H218O.Instead, 9,10-anthraquinone is suggested to be formed in the N2O4-based and in other related systems via foll ow-up reactions to an initial 1,4-addition across the 9,10 positions of anthracene.
- Radner, Finn
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- SOME NEWER ASPECTS OF CLEMMENSEN REDUCTION OF AROMATIC KETONES
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9,9'-Bifluorenyl (6), 1,2,2,2-tetraphenylethane (10) and 10,10'-bianthrone (18) have been obtained as a new type of products in Clemmensen reduction of 9H-fluoren-9-one (3), benzophenone (7) and 9,10-anthraquinone (13) respectively.Dibenzochrysene (5) is formed as the major product in the reduction of 3.Plausible mechanistic pathways for the formation of the unconventional products have been delineated.
- Talapatra, Sunil K.,Chakrabarti, Syamal,Mallik, Asok K.,Talapatra, Bani
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p. 6047 - 6052
(2007/10/02)
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- Chemical and Physical Properties of Anthronylidene
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Irradiation of diazoanthrone (DAAN) leads to loss of nitrogen and to formation of the carbene anthronylidene (AN).The triplet ground state of this carbene was detected at low temperature by ESR and optical spectrometric methods and at room temperature in fluid solution by laser flash photolysis.The rate constants for the reaction of 3AN with olefins, saturated hydrocarbons, and alcohols were determined spectrometrically.Combination of these kinetic measumerents with the results of chemical competition studies permits estimation of the energy gap separating the ground triplet state from the lowest singlet state of AN(ΔGST) to be 5.8 +/- 0.6 kcal/mol.This value is compared with that of other related carbenes and with the estimate obtained from MINDO/3 calculations for AN.
- Field, Kurt W.,Schuster, Gary B.
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p. 4000 - 4006
(2007/10/02)
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- ELECTROCHEMISTRY AT ANTHRACENE CRYSTAL/AQUEOUS NO2-, NO3- SOLUTION INTERFACE
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Holes (radical cations) were injected into one face of an anthracene crystal slab and discharged at the other face, which was in contact with a neutral aqueous solution containing 1 M NO3- or NO2-.Hole current densities (J) of up to 700 μAcm-2 generated a variety of surface oxidation products including anthraquinone, 9-nitroanthracene (9NA), oxanthrone, anthrone, bianthronyl (BA), and 9,10-dinitroanthracene with both NO3- and NO2- solutions.The amount of BA and 9NA increased as J2.With increasing NO3- concentration, the amount of 9NA produced increased, while that of BA decreased.It was concluded that 9NA is made by cooperation of two holes on adjoining molecules at defect sites.
- Leong, Baldwin,Pope, Martin,Steigman, Joseph
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p. 2506 - 2511
(2007/10/02)
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- Studies on the oxidation behaviour of dithranol
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When Dithranol is oxidized in a weakly alkaline buffer by air oxygen one has to discuss two different oxidative pathways. Under homogeneous conditions (dithranol dissolved) the only oxidation product is dithranol-dimer (and subsequently dithranol-brown) whereas under heterogeneous conditions (dithranol suspended) mainly chrysazine (dantron) is produced, which does not alter under the chosen conditions. These circumstances may play an important part in the dithranol therapy of psoriasis.
- Schaltegger
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p. 666 - 668
(2007/10/02)
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- The photochemistry of 9,10-anthracenedione in sulfuric acid solution. The dependence of product yields on reaction conditions
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Irradiation of a sulfuric acid solution of 9,10-anthracenedione with near-uv light generated 2-hydroxy-9,10-anthracenedione as the major product.In addition, the 1-hydroxy and polyhydroxy derivatives and the reduction products anthrone and bianthronyl were also formed.The yields of these minor products were markedly influenced by the concentrations of water and oxygen in the sulfuric acid.At low light intensities, oxygen quenched the efficient formation of the hydroxyanthracenediones and also oxidised the initial quinone reduction products.Photoreduction of the anthracenedione and photooxidation of anthrone occurred simultaneously in the solution.The reaction mechanism is more complex than previous studies indicated.
- Broadbent, A. Douglas,Stewart, John M.
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p. 1965 - 1969
(2007/10/02)
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- Palladium(II)-Catalysed Aromatic Coupling and Substitution: Reactions of Anthracene, Phenanthrene, Diphenyl Ether and Diphenylamine
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Anthracene when refluxed with Pd(OAc)2 in glacial HOAc affords 9,9'-bianthranyl (1) in poor yield along with traces of para-anthracene (2), the major product being anthraquinone.Addition of small amount of HClO4 in the above reaction totally suppresses the coupling reaction and gives anthraquinone as the exclusive product in much better yield.Treatment of anthracene with Pd(OAc)2 in the presence of Pb(OAc)4 affords 9-acetoxyanthracene (4), anthraquinone and dianthrone (5).The observed divergence in the product profile with anthracene in the above reactions from those with its lower homologues has been rationalised.Intramolekular Pd(II)-catalysed aryl-aryl coupling reactions of diphenyl ether and diphenylamine have also been studied.It is observed that while the former is almost unreactive towards Pd(OAc)2 in HOAc, the latter is converted into carbazole in fairly good yield under identical reaction condition.
- Majumder, P. L.,Joardar, M.
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p. 1191 - 1193
(2007/10/02)
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- Photochemical Hydroxylation of Anthracene-9,10-dione in Sulphuric Acid Solution
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Near u.v. irradiation of anthracene-9,10-dione in deoxygenated 96percent H2SO4 generates the sulphate ester of 2-hydroxyanthracene-9,10-dione in high yield along with the 1-hydroxy isomer and the novel reduction products anthracen-9(10H)-one and 9,9'-bianthracene-10,10'(9H,9'H)-dione; contrary to previous results, the product distribution and the rate of reaction are dependent upon the concentration of O2 in the solution.
- Broadbent, A. Douglas,Stewart, John M.
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p. 676 - 677
(2007/10/02)
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