- A convenient synthesis of 3-benzoylisoxazoles by 1,3-dipolar cycloaddition
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A convenient, efficient method for the preparation of 3-benzoylisoxazoles is described. Nitrile oxides generated in situ from phenylglyoxylohydroxamyl chlorides and NaHCO3 in isopropyl alcohol smoothly react with dipolarophiles at room temperat
- Kai, Hiroyuki,Tomida, Minoru,Nakai, Toru,Takase, Akira
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p. 2299 - 2308
(2007/10/03)
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- Additions of azomethine ylides to fullerene C60 assisted by a removable anchor
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The addition of nitrile oxides to [60]fullerene, leading to isoxazolinofullerenes, can be reversed using reducing agents such as Mo(CO)6 or DIBALH. Thus, this reaction can be used; in principle, for protection/deprotection of [60]fullerene or f
- Da Ros, Tatiana,Prato, Maurizio,Lucchini, Vittorio
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p. 4289 - 4297
(2007/10/03)
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- Preparation and mechanism of solvolysis of N-hydroxy-α- oxobenzeneethanimidoyl chloride, a 2-(hydroxyimino)-1-phenylethan-1-one derivative: Molecular structure of α-oxo-oximes (=α-(hydroxyimino) ketones)
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Acid-catalyzed methanolysis of N-hydroxy-α-oxobenzeneethanimidoyl chloride (1), a 2-(hydroxyimino)-1-phenylethan-1-one derivative obtained in one step from acetophenone, leads to a constant ratio of methyl α- oxobenzeneacetate (2) and methyl α-(hydroxyimino)benzeneacetate (3). 13C(α) Labelled [13C]-1 affords 13C(α) labelled [13C]-3, thus discarding the hypothesis of its formation via 1,2-arene migration. The reported sequence opens a novel approach to phenylglyoxylic and mandelic acid esters (=α-oxobenzeneacetic and α-hydroxybenzeneacetic acid esters), from acetophenone. The molecular structures of 1 and 3 were determined by X-ray structure analysis and compared with previously reported crystallographic data of α-oxo-oximes (=α-(hydroxyimino) ketones) 4 and 6-8. The unique stereoelectronic characteristics of the α-oxo-oxime moiety are discussed. All α-oxo-oximes share the following structural characteristics: (E)- configuration of the oxime C=N-OH bond (i.e. OH and C=O trans), the s-trans conformation of the oxo and imino moieties about the C(α)-C(=NOH) single bond, and intermolecular H-bonding. They differ from the isostructural α- diketone enols by the absence of resonance-assisted intramolecular H-bonding.
- Hamersak, Zdenko,Peric, Berislav,Kojic-Prodic, Biserka,Cotarca, Livius,Delogu, Pietro,Sunjic, Vitomir
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p. 1289 - 1301
(2007/10/03)
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- Nonquaternary cholinesterase reactivators. 4. Dialkylaminoalkyl thioesters of α-keto thiohydroximic acids as reactivators of ethyl methylphosphonyl- and 1,2,2-trimethylpropyl methylphosphonyl-acetylcholinesterase in vitro
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In the search for improved lipophilic centrally active acetylcholinesterase (AChE) antidotes, a series of α-keto thiohydroximates were prepared and evaluated for their ability to reactivate AChEs inhibited by ethyl p-nitrophenyl methylphosphonate (EPMP) and soman (GD). The compounds conformed to the general structure 4-RC6H5C-(O)C(NOH)S(CH2)(n)N+R'R''·X- where R = H, CH3, F, Br, Cl, OCH3, CN; R' = CH3, C2H5, i-C3H7; R'' = H, CH3; X = Cl, I; and n = 2, 3. In this series, varying R substituents on the aryl ring produced compounds with oxime pK(a) values from 6.8 to 8.0, optimum for an AChE reactivator. Increasing lipophilicity of the amine segment correlated with reactivator potency, as did electron-withdrawing groups on the aryl moiety, presumably due to increased binding to hydrophobic sites surrounding the AChE active site. The in vitro reactivation potency of the α-keto thiohydroximates approaches and even surpasses that of 2-PAM and toxogonin for GD-inhibited AChE. These initial findings point to additional structure-activity relationships to assist in the design of improved antidotal compounds.
- Bedford,Miura,Bottaro,Howd,Nolen III
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p. 1689 - 1696
(2007/10/02)
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- NEW SYNTHESES OF α-OXIMINO-α-HALOKETONES : REACTIONS OF α-HALOKETONES WITH ALKYL THIONITRITES
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α-Oximo-α-haloketones were readily synthesized in good yields by treating α-haloketone with alkyl thionitrites under mild conditions.
- Kim, Yong Hae,Jung, Sun Ho
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p. 2371 - 2372
(2007/10/02)
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