6012-97-1Relevant articles and documents
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Geering
, p. 1128 (1959)
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Octachloroazulene
Lou, Yan,Chang, Joanne,Jorgensen, Jeffrey,Lemal, David M.
, p. 15302 - 15307 (2002)
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.
Halogenation Using Quaternary Ammonium Polyhalides. XXXI. Halogenation of Thiophene Derivatives with Benzyltrimethylammonium Polyhalides
Okamoto, Tsuyoshi,Kakinami, Takaaki,Fujimoto, Hiroshi,Kajigaeshi, Shoji
, p. 2566 - 2568 (2007/10/02)
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.
Thiophene S,N-Ylides: A New Versatile Class of Sulphimides
Meth-Cohn, Otto,Vuuren, Gerda van
, p. 233 - 244 (2007/10/02)
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.