Phenol oxidation mechanisms. A search for phenoxylium intermediates

Hewitt, D. G.

doi:10.1039/j39710001750

Cited by 10 publications

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“…The spirodienone derivatives of substituted and unsubstituted bis(naphthol)methanes have been the subject of numerous studies and remain one of the most thoroughly studied members of the spirodienone family [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The Abel's ketone 2 was also prepared by oxidizing 1 with NaBiO 3 in refluxing benzene in 3 hours [18].…”

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confidence: 99%

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Oxidation of bisnaphthols to spironaphthalenones, revisited

Khoramabadi-zad¹,

Yavari²,

Shiri³

et al. 2008

Journal of Heterocyclic Chem

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Bis(2-hydroxy-1-naphthyl)methane derivatives have been efficiently converted to their corresponding spirans through three methods, i.e. oxidation by TCCA under mild reaction conditions, Ph 3 Bi catalyzed air oxidation, and by electrochemical reaction. The first two methods are diastereoselective and give either of the two possible diastereomers, while the electrochemical method produces equal amounts of these diastereomers.

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Section: Introductionmentioning

confidence: 99%

“…The Abel's ketone 2 was also prepared by oxidizing 1 with NaBiO 3 in refluxing benzene in 3 hours [18].…”

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confidence: 99%

Oxidation of bisnaphthols to spironaphthalenones, revisited

Khoramabadi-zad¹,

Yavari²,

Shiri³

et al. 2008

Journal of Heterocyclic Chem

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“…C2,HI2N2O2 requires C,79.3;H,3.5;N,8. (4e) with o-Chlorani1.-A solution of the bisnaphthol(4e) (300 mg) in dry benzene (100 ml) was refluxed with o-chloranil(500 mg) for 15 h. After concentration the reaction mixture was chromatographed over neutral alumina. Elution with ethyl acetate gave the dicyanospironaphthalenone (5). No other products were isolated.…”

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confidence: 99%

“…These spectral data indicated the presence of two a$-unsaturated carbonyl groups. To obtain further t The numbering used for compounds (5) and 6is not systematic but is used for consistency with compounds (12) and (13). The letters in the parentheses indicate the nature of the signal in the offresonance decoupled spectrum; very similar values may be interchanged, details of the structure, the 13C n.m.r.…”

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Oxidation of bis(2-hydroxy-1-naphthyl)methane and similar bisnaphthols with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. Structure and synthesis of novel products

Kasturi¹,

Rajasekhar²,

Raju³

et al. 1984

J. Chem. Soc., Perkin Trans. 1

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Oxidation of bis(2-hydroxy-1-naphthyl)methane (4a) with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) has been shown to give the novel compounds, cis-and trans-dispiro(naphtha1ene-1,2'(1'H)-naphtho[2,1-b)pyran-3',1 "-naphthalene}-2(1 H),2"(1 "H)-dione (1 2a) and (13a) together with the quinone methide dimer (6a) and the spiroketone (5a). Compounds (12a) and (13a) were characterised on the basis of their spectral properties and the structures were finally confirmed by an Xray crystal structure analysis of (1 2a). Hydrogenation of compounds (I 2a) and (1 3a) has been shown t o give the dihydroxy compound (14) via CC bond cleavage. An alternative synthesis of the dispironaphthalenones (12a) and (13a) was achieved by oxidation of the dihydroxy compound (14), prepared by an independent method. The generality of the oxidation of bisnaphthols of type (4a) to give novel products of the type (1 2a) and (13a) has been shown by studying the oxidation of the variously substituted bisnaphthols (4b-d,f) with DDQ. A mechanism has been proposed invoking the intermediacy of the quinol ethers (22) and (24).

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“…[29]): 2,48 (s, CH3-C(3)); 6,98-7,59 (m, 4 H-C (4-7)). -MS.: 133 (100,M'), 105(42),92(11),90 (16),78(11),64 (28),63 (26),51 (7), 50 (7),39(12), 38(11 3. 3,5-Dimethyl-I,2-benzisoxazol (lc).…”

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Zur Photochemie von 1, 2‐Benzisoxazolen in stark saurer Lösung

Doppler

Schmid

Hansen

1979

Helvetica Chimica Acta

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On the Photochemistry of 1,t-Benzisoxazoles in Strongly Acidic Solution SummaryThe 1,2-benzisoxazoles l a , l b and Id when dissolved in 96% sulfuric acid and irradiated through a quartz filter with a mercury high-pressure lamp yield, after work-up, mixtures of 2,5-and 2,3-dihydroxy-acylbenzenes (2 and 3, respectively; cJ: Schemes 1 and 3 and Table I ) . Irradiation of 3,5-dimethyl-l, 2-benzisoxazole (lc) in 96% sulfuric acid leads to the formation of 2,3-dihydroxy-5-methyl-acetophenone (3c) in only 6% yield (cJ Table 1). It is assumed that the 1,2-benzisoxazolium ions react in the excited singlet state by heterolytic cleavage of the N, 0-bond to yield the corresponding aryl oxenium ions 7 in the singlet ground state (see Scheme 5). Reaction of 7 with HS04@ ions, present in 96% sulfuric acid, yields, after hydrolysis, the dihydroxy compounds 2 and 3. Photolysis of 3-methyl-1,2-benzisoxazole (lb) in diluted sulfuric acid (0,5 to 9~) in methanol or water leads only to the formation of 2-amino-phenol (6; see Scheme 3), presumable via photo-isomerization of 1 b to 2-methylbenzoxazole (5b) which then is hydrolyzed to give 6. 1. Einleitung. -Aryloxenium-Ionen und ihre Reaktionen sind noch nicht sehr eingehend untersucht worden. Sie spielen als reaktive Zwischenprodukte sicher eine Rolle bei der Thiele-Winter-Reaktion (vgl. [2]) und konnten auch bei der elektrochemischen Oxydation von Phenolen auftreten (vgl. [3] [4] und dort zitierte Literatur). Aryloxenium-Ionen sind auch interessant als mogliche Zwischenstufen bei biosynthese-ahnlichen oxydativen oder auch bei elektrochemischen ). Auch die Thermolyse von 1-(p-Nitrophenoxy)-pyridinium-tetrafluoroborat scheint uber p-Nitrophenyloxenium-Ionen zu verlaufen [lo].

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Phenol oxidation mechanisms. A search for phenoxylium intermediates

Cited by 10 publications

References 0 publications

Oxidation of bisnaphthols to spironaphthalenones, revisited

Oxidation of bisnaphthols to spironaphthalenones, revisited

Oxidation of bis(2-hydroxy-1-naphthyl)methane and similar bisnaphthols with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. Structure and synthesis of novel products

Zur Photochemie von 1, 2‐Benzisoxazolen in stark saurer Lösung

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