- Ru-Photoredox-Catalyzed Decarboxylative Oxygenation of Aliphatic Carboxylic Acids through N-(acyloxy)phthalimide
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Decarboxylative aminoxylation of aliphatic carboxylic acid derivatives with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) in the presence of ruthenium photoredox catalysis is reported. The key transformation entails a highly efficient photoredox catalytic cycle using Hantzsch ester as a reductant. The ensuing alkoxyamine can be readily converted to the corresponding alcohol in one pot, representing an alternative approach to access aliphatic alcohols under photoredox conditions.
- Zheng, Chao,Wang, Yuting,Xu, Yangrui,Chen, Zhen,Chen, Guangying,Liang, Steven H.
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p. 4824 - 4827
(2018/08/24)
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- Application of complementary mass spectrometric techniques to the identification of ketoprofen phototransformation products
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Ketoprofen (KP) is a nonsteroidal anti-inflammatory drug, which during UV irradiation rapidly transforms into benzophenone derivatives. Such transformation products may occur after topical application of KP, which is then exposed to sunlight resulting in a photo-allergic reaction. These reactions are mediated by the benzophenone moiety independently of the amount of allergen. The same reactions will also occur during wastewater or drinking water treatment albeit their effect in the aqueous environment is yet to be ascertained. In addition, only a few such transformation products have been recognised. To enable the detection and structural elucidation of the widest range of KP transformation products, this study applies complementary chromatographic and mass spectrometric techniques including gas chromatography coupled to single quadrupole or ion trap mass spectrometry and liquid chromatography hyphenated with quadrupole-time-of-flight mass spectrometry. Based on structural information gained in tandem and multiple MS experiments, and on highly accurate molecular mass measurements, chemical structures of 22 transformation products are proposed and used to construct an overall breakdown pathway. Among the identified transformation products all but two compounds retained the benzophenone moietya€"a result, which raises important issues concerning the possible toxic synergistic effects of KP and its transformation products. These findings trigger further research into water treatment technologies that would limit their entrance into environmental or drinking waters. Copyright
- Kosjek, Tina,Perko, Silva,Heath, Ester,Kralj, Bogdan,Zigon, Dusan
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experimental part
p. 391 - 401
(2011/11/12)
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- Formal intramolecular photoredox chemistry of meta-substituted benzophenones
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(Chemical Equation Presented) Photolysis of 3-(hydroxymethyl)benzophenone (1) in aqueous solution (pH -4 M) conditions. Evidence suggests that the highly efficient (Φ ~ 0.6) reaction involves a unimolecular mechanism and an overall formal intramolecular photoredox process, which requires electronic communication between the 1,3-positions of the benzene ring, an unprecedented example of the photochemical meta effect. The photoredox reaction was not observed in organic solvents, where only photoreduction of the benzophenone moiety was observed.
- Mitchell, Devin,Lukeman, Matthew,Lehnherr, Dan,Wan, Peter
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p. 3387 - 3389
(2007/10/03)
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- Photochemical and photobiological properties of ketoprofen associated with the benzophenone chromophore.
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Irradiation of ketoprofen in neutral aqueous medium gave rise to 3-ethylbenzophenone as the major photoproduct. Its formation is justified via protonation of a benzylic carbanion or hydrogen abstraction by a benzylic radical. Minor amounts of eight additional compounds were isolated. Four of them are derived from the benzylic radical: 3-(1-hydroperoxyethyl)benzophenone, 3-(1-hydroxyethyl)benzophenone, 3-acetylbenzophenone and 2,3-bis-(3-benzoylphenyl)butane. The other four products involve initial hydrogen abstraction by the excited benzophenone chromophore of ketoprofen: 1,2-bis-(3-ethylphenyl)-1,2-diphenyl-1,2-ethanediol, 2-(3-benzoylphenyl)-1-(3-ethylphenyl)-1-phenylpropan-1-ol, alpha-(3-ethylphenyl)phenylmethanol, 1,2-bis-[3-(2-hydroxycarbonylethyl) phenyl]-1,2-diphenyl-1,2-ethanediol. The latter process was found to mediate the photoperoxidation of linoleic acid through a type I mechanism, as evidenced by the inhibition produced by the radical scavengers butylated hydroxyanisole and reduced glutathione. The major photoproduct, which contains the benzophenone moiety but lacks the propionic acid side chain, also photosensitized linoleic acid peroxidation. Because lipid peroxidation is indicative of cell membrane lysis, the above findings are highly relevant to explain the photobiological properties of ketoprofen.
- Bosca,Miranda,Carganico,Mauleon
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- OXIDATIVE DECARBOXYLATION OF CARBOXYLIC ACIDS BY IRON PORPHYRIN - IODOSYLBENZENE SYSTEM
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An iodosylbenzene - iron tetraarylporphyrin catalyst system decarboxylated α-aryl carboxylic acids and α,α,α-trisubstituted acetic acids efficiently to give the corresponding alcohol and carbonyl derivatives.
- Komuro, Masakatsu,Nagatsu, Yoshio,Higuchi, Tsunehiko,Hirobe, Masaaki
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p. 4949 - 4952
(2007/10/02)
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- Method for preparing 3-ethylbenzophenone
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The present invention provides a method for preparing 3-ethylbenzophenone in a high purity which comprises the steps of alkylating benzene with ethylene with the aid of an alkylating catalyst to obtain an alkylated product composed mainly of unreacted benzene, ethylbenzene, polyethylbenzenes and heavier by-products; subjecting the alkylated product to distillation in order to recover therefrom a fraction which has a temperature range of boiling points within the range of 275° to 310° C. (in terms of atmospheric pressure); dehydrogenating the recovered fraction at a reaction temperature within the range of 200° to 700° C. in the presence of a dehydrogenating catalyst; oxidizing the dehydrogenated fraction in a liquid phase; and performing distillation to recover therefrom 3-ethylbenzophenone represented by the formula: STR1
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- 1,1-(3-ethylphenyl)phenylethylene and method for preparing it
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The present invention is concerned with a novel intermediate 1,1-(3-ethylphenyl)phenylethylene represented by the formula (I) and its manufacturing method, and according to the present invention, Ketoprofen can be synthesized at a low cost and in a high y
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