- Charge control in the S(N)Ar reaction. Meta substitution with respect to the activating nitro group in 3,4-dihalogenonitrobenzenes
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The reactions of 3-fluoro-4-chloronitrobenzene and of 3,5-difluoro-4-chloronitrobenzene with thiophenoxide anion lead to predominant substitution of the chlorine atom through S(N)Ar orbital-controlled processes. However, when harder nucleophiles (methoxide anion) are used, the substitution of a fluorine atom meta with respect to the activating nitro group becomes apparent in the reaction of 3-fluoro-4-chloronitrobenzene, predominant in the reaction of 5-fluoro-4-chloro-3-methyoxynitrobenzene, and almost exclusive in the reaction of 3,5-difluoro-4-chloronitrobenzene. Kinetic measurements and theoretical calculations indicate that the observed meta substitution of a fluorine atom is a S(N)Ar charge-controlled reaction with a loosely bonded transition state.
- Cervera,Marquet,Martin
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- Degradation products of a phenylurea herbicide, diuron: Synthesis, ecotoxicity, and biotransformation
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The degradation products of diuron (photoproducts and metabolites), already described in the literature, were synthesized in order to carry out further investigations. Their ecotoxicity was determined using the standardized Microtox test, and most of the derivatives presented a nontarget toxicity higher than that of diuron. Therefore, the biotransformation of these compounds was tested with four fungal strains and a bacterial strain, which were known to be efficient for diuron transformation. With the exception of the 3,4-dichlorophenylurea, all the degradation products underwent other transformations with most of the strains tested, but no mineralization was observed. For many of them, the biodegradation compound for which the toxicity was important was 3,4-dichlorophenylurea. This study underlines the importance of knowing the nature of the degradation products, which has to be kept in mind while analyzing natural water samples or soil samples.
- Tixier,Sancelme,Bonnemoy,Cuer,Veschambre
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- Halogenation and DNA cleavage via thermally stable arenediazonium camphorsulfonate salts
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A series of stable arenediazonium camphorsulfonate salts (2a-2j) were synthesized by simple diazotization of several aromatic amines in the presence of sodium nitrite and camphorsulfonic acid. All the new arenediazonium camphorsulfonates, which were characterized by multinuclear (1H and 13C) NMR, IR, DSC, and X-ray diffraction analysis (2e and 2f) provide unambiguous proof for the molecular structures of 2e and 2f. The efficient application of these salts in halogenation reactions was studied in solvent and solvent-free conditions and the DNA cleavage activity was also assessed. These arenediazonium camphorsulfonate salts are noticed as efficient DNA cleaving agents.
- Vajpayee, Vaishali,Moon, Mi Eun,Lee, Sunmi,Ravikumar, Sambandam,Kim, Hyunuk,Ahn, Byungchan,Choi, Seoyoon,Hong, Soon Ho,Chi, Ki-Whan
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p. 3511 - 3517
(2013/04/23)
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- An expeditious and environmentally benign preparation of aryl halides from aryl amines by solvent-free grinding
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An efficient solvent-free methodology for conversion of various aryl amines into bromides and chlorides via arenediazonium tosylate salts under grinding conditions is disclosed. This new methodology not only avoids the use of strong acids and expensive reagents for diazotization-halogenation reactions, but also decreases the amount of organic waste from the reaction process.
- Moon, Mi Eun,Choi, Younghwa,Lee, Young Min,Vajpayee, Vaishali,Trusova, Marina,Filimonov, Victor D.,Chi, Ki-Whan
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scheme or table
p. 6769 - 6771
(2011/03/17)
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- Efficient and economic halogenation of aryl amines via arenediazonium tosylate salts
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Arenediazonium tosylate salts have been successfully employed as a new and efficient reagent in halogenation reactions. A novel and economic protocol has been developed for the bromination and chlorination of various anilines using arenediazonium tosylate salts. A wide variety of reaction conditions were studied in acetonitrile at either room temperature or 60 °C in the presence or absence of catalyst with good to excellent yields. A surprising result showed the formation of acetanilides as a major product of aniline and methyl-substituted aniline halogenations in high yields.
- Lee, Young Min,Moon, Mi Eun,Vajpayee, Vaishali,Filimonov, Victor D.,Chi, Ki-Whan
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experimental part
p. 7418 - 7422
(2010/10/01)
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- ARYL SULFONAMIDES
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Compounds are provided that act as potent antagonists of the CCR9 receptor, and which have been further confirmed in animal testing for inflammation, one of the hallmark disease states for CCR9. The compounds are generally aryl sulfonamide derivatives and are useful in pharmaceutical compositions, methods for the treatment of CCR9-mediated diseases, and as controls in assays for the identification of CCR9 antagonists.
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- Compounds for the modulation of PPARgamma activity
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Modulators of PPARγ activity are provided which are useful in pharmaceutical compositions and methods for the treatment of conditions such as type II diabetes and obesity.
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- Oxidation dye for keratinic fibers containing 2-halo-5-acetaminophenol as a coupler
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A dye composition for keratinic fibers comprising in combination: A. at least one oxidation base selected from the group consisting of an aromatic or heterocyclic compound carrying either two amino groups or one amine group and one hydroxy group, fixed in para position relative to each other on the aromatic or heterocyclic nucleus of said compound, said oxidation base being in the form of a free base or in the form of an acid addition salt thereof; and B. at least one coupler of the formula: SPC1 Wherein X represents a member selected from the group consisting of F, Cl or Br.
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