- Energetic Sila-Nitrocarbamates: Silicon Analogues of Neo-Pentane Derivatives
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Four silanes based on the neo-pentane skeleton Me4-xSi(CH2R)x containing carbamate groups (x = 1-4, R = OC(O)NH2) have been prepared via the corresponding alcohols Me4-xSi(CH2OH)x, starting from the chlorosilanes Me4-xSiClx. Subsequent nitration leads to the corresponding primary nitrocarbamates (R = OC(O)NHNO2), examined for the purpose as potential energetic materials, including the silicon analogue of pentaerythritol tetranitrocarbamate (sila-PETNC) and a siloxane based nitrocarbamate side-product. All compounds were thoroughly characterized by spectroscopic methods including X-ray diffraction. Thermal stabilities and sensitivities toward impact and friction were examined, as well as detonation values by calculating energies of formation using the EXPLO5 V6.02 software.
- Axthammer, Quirin J.,Klap?tke, Thomas M.,Krumm, Burkhard,Reith, Thomas
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- Hydrodechlorination of (CH3)3SiCHCl2 over Pd, Ni, Co and Fe supported on AlF3
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Gas phase hydrodechlorination (HDC) process of Me3SiCHCl 2 was studied in a flow reactor at 200 °C using a 2% metal loading (w/w) of four different monometallic catalysts (Pd/AlF 3, Ni/AlF 3,Co/AlF 3 and Fe/AlF 3). The catalysts were prepared by sol-gel method and structurally examined by BET method, FT-IR and XPS techniques. The XPS technique showed that Ni II, Fe III and Co III exist as oxides. The major products in the HDC process of Me 3SiCHCl 2 were identified by GC and GC-MS and found to include Me 3SiCH 2Cl, Me 3SiCl, and Me 4Si. The effect of these catalysts on the quantitative conversion, selectivity and conversion rates are reported. [Figure not available: see fulltext.]
- Hina, Rateb,Arafa, Isam,Ennab, Omar
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- Preparative catalytic chlorination of adamantane, cyclohexane, and hexane in the system tetrachloromethane-MX2(PPh3)2 (MX2 = PdBr2, PtCl2)-acetonitrile-potassium carbonate
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Heating of saturated hydrocarbons RH (cyclohexane, adamantane, and hexane) with tetrachloromethane in the presence of acetonitrile, potassium carbonate, and catalytic amounts of dihalide triphenylphosphine complexes of palladium(II) or platinum(II), MX2(PPh)2 (MX2 = PdBr2, PtCi2), for 6-8 h at 120°C yields monochlorinated derivatives of the respective hydrocarbons in 30-55% yield. Benzene, toluene, ethylbenzene, and tetramethylsilane show low reactivity under the conditions adopted for the reaction. Relative reactivity of various bond types C-H of alkanes is in agreement with the well known sequence: tertiary > secondary > primary. A scheme is proposed assuming trichloromethyl radicals as active species, and the catalyst function consists in activating C-C1 bond of the tetrachloromethane.
- Vedernikov,Sayakhov,Zazybin,Solomonov
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p. 812 - 815
(2007/10/03)
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- Photochemical Sulfochlorination of Tetramethylsilane and Hexamethyldisiloxane
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Reaction of sulfuryl chloride with tetramethylsilane and hexamethyldisiloxane and effect of photocatalysts, such as yttrium(III) chloride and sulfur, on this reaction were studied. Hydrolysis and ammonolysis of chlorosulfonylmethyl(trimethyl)silane are shown to be useful for preparing trimethylsilyl-methanesulfonic acid and its amide.
- Bol'shakova,Vlasova,Pozhidaev,Voronkov
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p. 712 - 714
(2007/10/03)
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- The synthesis of -substituted dialkyldichlorosilanes and their conversion into polysiloxanes
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Attack of the oxyl (CF3)2NO. (1) on an ethyl group of the silane Et2SiCl2 occurs at both the α- and β-positions relative to silicon (ratio 31:45), whereas with the silane PrnSiMeCl2 attack takes place at the β-position of the propyl group.With the disilane Me3SiCH2SiMe3, the mojor silicon-containing products formed from treatment with oxyl 1 are Me3SiF, (CF3)2NOSiMe3 and Me3SiSiMe3.Speier-catalysed (H2PtCl6) addition of the silane HSiCl2X (X = Me and Cl) to the alkene (CF3)2NOCH2CH=CH2 gives the adducts (CF3)2NOCH2CH2CH2SiCl2X (29, X = Me) and (28, X = Cl)in high yield.The substituted dichlorosilanes (CF3)2NOCH2CH2SiEtCl2 (9), (CF3)2NOCHMeCH2SiMeCl2 (14) and (CF3)2NOCH2CH2CH2SiMeCl2 (29) are converted into corresponding polysiloxanes ("prepolymers" of low molecular weight) by reaction with reagents including water, acid, base and metal oxides; equilibration of the polysiloxane "prepolymer" 38, derived from dichlorosilane 29 by heating with powdered KOH, affords a solid rubbery polysiloxane.
- Ducker, Graham E.,Tipping, Anthony E.
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p. 253 - 262
(2007/10/02)
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- Diarylstrylquinoline diacids and pharmaceutical compositions thereof
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Compounds having the formula: STR1 are leukotriene antagonists and inhibitors of leukotriene biosynthesis. These compounds are useful as anti-asthmatic, anti-allergic, anti-inflammatory, and cytoprotective agents.
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- Electrosynthese en chimie organosilicique: silylation selective de polychloromethanes
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Silylation by electroreduction of carbon tetrachloride, chloroform or methylene chloride is more selective than the common organometallic route.Me3SiCCl3 (94percent) and (Me3Si)2Cl2 (68percent) were thus obtained from CCl4, Me3SiCHCl2, (94percent) and (Me3Si)2CHCl (56percent) from CHCl3 and Me3SiCH2Cl (90percent) from CH2Cl2.Complete silylation of polychloromethanes was also successful by electrosynthesis and gave satisfactory yields.
- Pons, P.,Biran, C.,Bordeau, M.,Dunogues, J.
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- SILYL-NITROGEN COMPOUNDS I. REACTIONS OF DILITHIUM BIS(TRIMETHYLSILYLL)HYDRAZINE WITH GROUP IV HALIDES
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Dilithium 1,2-bis(trimethylsilyl)hydrazine (1) reacts with CCl4, Me3SiCCl3 and CBr4 to form predominantly bis(trimethylsilyl)aminocarbonimidic dichloride, bis(trimethylsilyl)aminoisocyanide and bis(trimethylsilyl)diazene, whereas similar reactions with HCCl3, HCI3, H2CCl2, H2CI2, C2H4Cl2 or C2H2Cl4 lead to increasing amounts of bis(trimethylsilyl)hydrazine.In addition to the hydrazone, (Me3Si)2N-N=CH(Cl), the reaction of 1 with CHCl3 forms a small amount of triazasilacyclopentane,.............. .In contrast, Me2SnCl2 reacts with 1 to give tetraazadistannacyclohexane (Me2Sn(NSiMe3)2)2, whereas SnCl4, SnCl2 and PbCl2 act mainly as oxidants and Me2SiCl2 forms polymers.Another product of the reaction of 1 with SnCl2 or PbCl2 is LiN(SiMe3)2 originating perhaps from LiNH(SiMe3) or (LiNN(SiMe3)2)2.
- Vasisht, Sham Kumar,Sood, Mohini,Sood, Nirupma,Singh, Gursharan
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- NOUVELLES UTILISATIONS DU TETRAMETHYLSILANE COMME AGENT DE METHYLATION DES CHLOROSILANES; VALORISATION DU METHYLTRICHLOROSILANE
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In the presence of catalytic amounts of AlCl3, the chlorosilanes MeSiCl3, ClMe2SiCH2Cl and PhSiCl3 convert Me4Si into Me3SiCl.In the first case, at 130 deg C, two by-products from the industrial synthesis of Me2SiCl2 provide the useful Me3SiCl as the unique product with a 44percent conversion ratio from Me4Si.From ClMe2SiCH2CL, the only products formed are Me3SiCl and Me3SiCH2Cl, which is a useful reagent for organic syntheses (formation ratio: 32percent), if the reaction is performed under atmospheric pressure, but if an autoclave is used EtMe2SiCl (88percent maximal yield) is obtained.
- Bordeau, M.,Djamei, S. M.,Calas, R.,Dunogues, J.
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p. 131 - 138
(2007/10/02)
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- CHEMISTRY OF THE ORGANOSILICON COMPOUNDS-165 2-TRIMETHYLSILYL-METHYL-1, 3-BUTADIENE-A VERSATILE BUILDING BLOCK FOR TERPENE SYNTHESIS
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Two types of synthetically useful reactions of 2-trimethylsilylmethyl-1,3-butadiene (7) are discussed.Reactions of 7 with acid chlorides, aldehydes, ketones and acetals activated by a Lewis acid give isoprenylated compounds, while 7 undergoes the Diels-Alder reaction whit dienophiles.High regiospecificity of the reaction qualifies 7 for a versatile building block of terpene synthesis.
- Sakurai, Hideki,Hosomi, Akira,Saito, Masaki,Sasaki, Koshi,Iguchi, Hirokazu,et al.
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p. 883 - 894
(2007/10/02)
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- STABILIZATION IN THE ORDER I>Br>Cl AMONG TRIMETHYLSILYLMETHYL HALIDES, COMPARED TO CARBON ANALOGS. POSSIBLE ROLE OF ELECTRONEGATIVITY IN ORGANOSILICON CHEMISTRY
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Electronegativities may be used to rationalize the observation that the equilibrium, CH3(CH2)3I + (CH3)3SiCH2Cl CH3(CH2)3Cl + (CH3)3SiCH2I, lies to the right.
- Peterson, Paul E.
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p. 1295 - 1298
(2007/10/02)
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