- Decarboxylative photosubstitution of dicyanobenzenes with aliphatic carboxylate ions
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The photoreaction of dicyanobenzenes with aliphatic carboxylate ions afforded alkylcyanobenzenes and alkyldicyanobenzenes via decarboxylative substitution. The redox-photosensitized reaction system was effective in improving the product yield. The efficie
- Itou, Tatsuya,Yoshimi, Yasuharu,Morita, Toshio,Tokunaga, Yuji,Hatanaka, Minoru
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experimental part
p. 263 - 269
(2009/04/07)
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- Hydroxide ion as electron source for photochemical Birch-type reduction and photodehalogenation
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The photochemical Birch-type reduction of arenes and the photodehalogenation of haloarenes by a hydroxide ion that acted as an electron source occurred in 2-PrOH. The efficiency of these photoreactions was dependent on the nature of the substrate, the concentration of NaOH, and the solvent used. These photoreactions provide an environmentally friendly method for the reduction of aromatic rings and dehalogenation.
- Yoshimi, Yasuharu,Ishise, Akihiro,Oda, Hiromu,Moriguchi, Yousuke,Kanezaki, Hiroki,Nakaya, Yukari,Katsuno, Kayoko,Itou, Tatsuya,Inagaki, Sho,Morita, Toshio,Hatanaka, Minoru
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p. 3400 - 3404
(2008/09/21)
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- PHOTOCHEMICAL REACTIONS OF ARENECARBONITRILES WITH ALIPHATIC AMINES. 2. EFFECT OF AMINE STRUCTURE ON AMINYL VS. alpha -AMINOALKYL RADICAL FORMATION.
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The photochemical reactions of 9-phenanthrenecarbonitrile with several secondary and primary amines and triethylamine have been investigated. Rate constants for fluorescence quenching by secondary and primary amines decrease with amine alpha -alkylation in spite of increased electron-donor ability of the more substituted amines. This trend is attributed to a steric effect on the equilibrium constant for reversible exciplex formation. The reactions of secondary and primary amines in nonpolar solvent result in selective N-H vs. alpha C-H transfer from amine to arene, via a singlet exciplex. The ratio of alpha -C-H/N-H transfer increases with alpha -alkylation and increased solvent polarity and is larger for secondary vs. primary amines.
- Lewis,Correa
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p. 194 - 198
(2007/10/02)
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- Radical ions in photochemistry, 15. The photosubstitution reaction between dicyanobenzenes and alkyl olefins
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The photosubstitution (electron transfer) reaction between 1,4-dicyanobenzene (1) and 2,3-dimethyl-2-butene (2), which gives 1-(4-cyanophenyl)-2,3-dimethyl-2-butene (3) and 3-(4-cyanophenyl)-2,3-dimethyl-1-butene (4), has been extended to other dicyanobenzene-olefin mixtures.Substitution of cyano group occurs when both 1 or 1,2-dicyanobenzene (5) are irradiated in acetonitrile solution, in the presence of 2 or cyclohexane (16).Under comparable conditions 1,3-dicyanobenzene (6) failed to react.Little or no substitution was observed in any case when the olefin was methylpropene (19).The results for 1 and 5 are in agreement with empirical free energy calculations (Weller equation) for the electron transfer process which, howover, fail to explain the general lack of reactivity of 1,3-dicyanobenzene.Phenanthrene (11) has been shown to photosensitize the photosubstitution reaction between dicyanobenzenes and 2.Under these conditions the olefin reacts with 6 predominantly at the 4-position, resulting in overall substitution of a hydrogen atom.This reaction occurs regiospecifically, resulting in the formation of only one of the two possible isomeric side chains.The mechanistic details of these reactions have been substantiated by means of deuterium labelling studies.The aromatic nitriles also undergo photosubstitution by 2, in acetonitrile-methanol solution, resulting in methanol-incorporated products.Whereas reaction with 1 or 5 results in substitution of a cyano group, 6 was observed to give isomeric dicyanocyclohexenes, resulting from initial reaction at the 4-position, followed by reduction.A detailed mechanism for this secondary photoreduction has been substantiated by deuterium labelling studies.The anomalous behaviour of 1,3-dicyanobenzene has been attributed to a difference in the reactivity of the radical anion.
- Borg, Robert M.,Arnold, Donald R.,Cameron, T. Stanley
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p. 1785 - 1802
(2007/10/02)
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- Photochemical Reactions of Aromatic Compounds. Part 34. Direct Photocyanation of Arenes with Sodium Cyanide in the Presence of Electron Acceptors
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Efficient photocyanation of various arenes with sodium cyanide in 9:1 acetonitrile-water occurs in the presence of such electron acceptors as p-dicyanobenzene, 1-cyanonaphthalene, or 9-cyanophenanthrene.Under nitrogen, photocyanation of phenanthrene, anthracene, naphthalene, and 2,3-dimethylnaphthalene gives both the corresponding hydrocyanation products and the aromatic nitriles, while complex mixtures are formed with other arenes.Under oxygen, a variety of arenes which are electron donors in nature can be efficiently cyanated upon irradiation to give the aromatic nitriles.Cyanation of naphthalene derivatives gives only 1-cyanonaphthalene compounds whereas phenanthrene and anthracene are cyanated at C-9.
- Yasuda, Masahide,Pac, Chyondgjin,Sakurai, Hiroshi
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p. 746 - 750
(2007/10/02)
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