- NEW METHOD FOR THE SYNTHESIS OF TETRACHLOROTHIOPHENE
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The reaction of tetrachloroethylene with hydrogen sulfide at 450-500 deg C leads to the formation of tetrachlorothiophene as the principal product, along with hexachlorobutadiene, the yield of which increases as the reaction temperature is raised.
- Voronkov, M.G.,Deryagina, E.N.,Perevalova, V.I.
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- Octachloroazulene
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The title compound, the first perhaloazulene, has been synthesized from hexachlorobutadiene and cyclopentadiene. Further chlorination of 1,3,4,5,6,7-hexachloroazulene results in addition, rot substitution, under electrophilic as well as free radical conditions. Radical chlorination of the hexachloro-azulene affords in good yield a single decachlorotetrahydroazulene. Treatment of this Cl10 compound with one equiv of a phosphazene base gives a nonachlorodihydroazulene, but the addition of a second equiv results in dechlorination to 1,2,3,4,5,6,7-heptachloroazulene as well as dehydrochlorination to octachloro-azulene. The former azulene is obtained cleanly from the Cl9 compound with acid catalysis or by reduction with mercury. In the presence of calcium carbonate, however, the Cl9 intermediate yields the dark green octachloroazulene. Although octachloronaphthalene is readily converted into its octafluoro counterpart, the isomeric octachloroazulene is far too sensitive to undergo the analogous transformation.
- Lou, Yan,Chang, Joanne,Jorgensen, Jeffrey,Lemal, David M.
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- Polychlorination of Thiophene. A Reinvestigation
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Some old controversies in the literature with regard to the structures of trichlorothiophenes have been elucidated.In the course of these studies, we found that the best method for the preparation of 2,3,5-trichlorothiophene is the direct chlorination of thiophene in the presence of catalytic amounts of ferric chloride.If 2,5-dichlorothiophene is available 2,3,5-trichlorothiophene can also be obtained in good yields through chlorination with thionyl chloride and sulfuryl chloride, using aluminum trichloride as catalyst.
- Temciuc, Marcel,Hoernfeldt, Anna-Britta,Gronowitz, Salo
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p. 791 - 796
(2007/10/03)
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- Halogenation Using Quaternary Ammonium Polyhalides. XXXI. Halogenation of Thiophene Derivatives with Benzyltrimethylammonium Polyhalides
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The reactions of thiophene derivatives with benzyltrimethylammonium tetrachloroiodate, benzyltrimethylammonium tribromide, and benzyltrimethylammonium dichloroiodate in acetic acid or in acetic acid-zinc chloride under mild conditions gave chloro-, bromo-, and iodo-substituted thiophene derivatives, respectively, in satifactory yields.
- Okamoto, Tsuyoshi,Kakinami, Takaaki,Fujimoto, Hiroshi,Kajigaeshi, Shoji
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p. 2566 - 2568
(2007/10/02)
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- Thiophene S,N-Ylides: A New Versatile Class of Sulphimides
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Tetrachlorothiophene reacts with methyl, ethyl, and phenyl azidoformates and with toluene-p-sulphonyl azide at 130-150 deg C to give stable thiophene S,N-ylides. 2,5-Dichloro and 2,5-dibromo-thiophene and tetrabromothiophene yield products derived by nitrene attack at the α-position.The S,N-ylides undergo ready photolysis to liberate the parent nitrene, and react with a wide variety of electron-rich dienophiles as 4?-components to give tetrachlorodihydrobenzenes with extrusion of a thionitroso compound.With dienes the ylides react either as 2?- or 4?-systems.Thus with anthracene a dihydrothiophene analogue of triptycene is generated efficiently aromatised and de-ylidated with zinc in methanol.With dimethyl acetylenedicarboxylate the ylides yield a thiazocine by a novel ring expansion.Oxidation of the ylide system with 3-chloroperbenzoic acid gives the corresponding ylide S-oxide.Tetrachlorothiophene also reacts efficiently with diazoalkanes under rhodium acetate catalysis to give thiophene S,C-ylides, which undergo cycloaddition with nucleophilic alkenes much more slowly than their nitrogen analogues.
- Meth-Cohn, Otto,Vuuren, Gerda van
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p. 233 - 244
(2007/10/02)
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- USEFUL NEW METHOD FOR PREPARATION OF PERCHLOROTHIOPHENE (RESEARCH IN THE FIELD OF CHLORINATION OF ORGANIC COMPOUNDS AND CONVERSION OF CHLORO DERIVATIVES).
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A new method for preparation of perchlorothiophene is proposed. The advantages of the method as compared to the other methods are: absence of toxic compounds like sulfur chlorides and easy isolation of the required product: chlorination of monovinylacetylene to 1,1,2,2,3,4-hexachlorobutane. Dehydrochlorination of the hexachlorobutane to 1,1,2,3,-tetrachloro-1,3-butadiene. The yield is 98. 2%. Reaction of 1,1,2,3-tetrachloro-1,3-butadiene with elemental sulfur to give 3,4,5-trichlorothiophene. Conversion of trichlorothiophene into perchlorothiophene by chlorination with gaseous chlorine. The experimental procedure is given.
- Akopyan,Kon'kova,Safaryan
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p. 1064 - 1065
(2007/10/02)
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- The Action of Nitrenes on Halogenothiophenes; Formation of Thiophene S,N-Ylides
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When ethyl or phenyl azidoformate, or p-tolylsulphonyl azide are decomposed in warm tetrachlorothiophene, tetrachlorothiophene S,N-ylides are formed; 2,5-dichloro-, 2,5-dibromo-, and tetrabromo-thiophene on the other hand give products arising from attack at the α-position followed by rearrangement.
- Meth-Cohn, Otto,Vuuren, Gerda van
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p. 190 - 191
(2007/10/02)
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- Annelations with Tetrachlorothiophene 1,1-Dioxide
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Tetrachlorothiophene 1,1-dioxide is a reactive, cheletropic Diels-Alder reagent.It has been used to annelate, with loss of sulfur dioxide, a large variety of olefinic compounds to form 1,2,3,4-tetrachloro-1,3-cyclohexadiene derivatives.Dehydrochlorination of these forms 1,2,4-trichloro aromatic compounds.Both double bonds in thiophene and N-methylpyrrole are annelated.Addition of tetrachlorothiophene dioxide to acyclic 1,5-dienes, which may contain a heteroatom, provides a facile synthesis of tetrachloroisotwistenes (51) and heteroisotwistenes (56) by a double Diels-Alder reaction.Acyclic 1,6-dienes lead to tetrachlorohomoisotwistene (59) and heterohomoisotwistenes (61).By use of 1,5-cyclooctadiene, sym-dibenzocyclooctatetraene, and 1,5-cyclononadiene, the more complex carbocycles 62, 65, and 66 are generated.Tetrabromothiophene dioxide reacts like the tetrachloro compound.
- Raasch, Maynard S.
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p. 856 - 867
(2007/10/02)
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