- Synthesis and structural characterization of 2,5-dihalo-3,4- dinitrothiophenes
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Using new nitration protocols, we have been able to efficiently dinitrate 2,5-dihalothiophenes with yields of ~80-95%. The resulting products 2,5-dibromo-3,4-dinitrothiophene (1), 2,5-dichloro-3,4-dinitrothiophene (2), 2-bromo-5-chloro-3,4-dinitrothiophene (3), as well as the analogous 2-bromo-3,4-dinitrothiophene (4), all crystallize easily allowing their characterization via X-ray crystallography. Crystallization of 1 occurs in the monoclinic space group C2/c with a=14.547(3)A, b=7.3534(15)A, c=10.775(2)A, β=128.89(3)°, and Z=4. Crystallization of 2 occurs in the tetragonal space group I-42d with a=9.9398(14)A, b=9.9398(14)A, c=16.866(3)A, and Z=8. Crystallization of 3 occurs as a pseudo-merohedral twin in the triclinic space group P-1 with a=7.340(5)A, b=8.094(5)A, c=9.112(5)A, α=82.059(5)°, β=66.232(5)°, γ=63.021(5)°, and Z=2. Crystallization of 4 occurs in the triclinic space group P-1 with a=7.1787(14)A, b=7.4092(15)A, c=8.3151(17)A, α=101.67(3)°, β=96.00(3)°, γ=116.13(3)°, and Z=2. The structures of all compounds exhibit the formation of interesting solid-state assemblies due to halogen-bonding interactions between the halogen and nitro groups. Springer Science+Business Media, LLC 2007.
- Wen, Li,Rasmussen, Seth C.
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- 2, 5-dichloro thiophene preparation method
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The present invention discloses a 2, 5-dichloro thiophene preparation method comprising the following steps: (1) an organic solvent and thiophene are added into a reaction vessel and warmed to reflux, under reflux conditions, batches of added N-chlorosucc
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Paragraph 0021; 0022
(2016/12/12)
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- Decarboxylative homocoupling of (hetero)aromatic carboxylic acids
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A variety of hetero(aromatic) carboxylic acids are shown to undergo decarboxylative homocoupling, mediated by a Pd/Ag system. This novel methodology for the synthesis of symmetrical biaryls avoids the use of haloarenes and organometallic compounds as starting materials.
- Cornella, Josep,Lahlali, Hicham,Larrosa, Igor
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supporting information; experimental part
p. 8276 - 8278
(2010/12/19)
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- Halogenation of Aromatic Compounds by N-chloro-, N-bromo-, and N-iodosuccinimide
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An efficient and mild method for the halogenation of aromatic compounds using N-chloro-, N-bromo-, and N-iodosuccinimide in the presence of NH 4NO3 or FeCl3 in acetonitrile was developed.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Satsumabayashi, Koko,Horaguchi, Takaaki
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p. 932 - 933
(2007/10/03)
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- Chlorinated thiophenes. Part 2. Trihalogenated hydroxythiophenes; preparation, reactions and tautomeric properties
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2-Hydroxy-3,4,5-trichlorothiophene (4), 3-hydroxy-4-bromo-2,5-dichlorothiophene (5) and 3-hydroxy-2,4,5-trichlorothiophene (6) have been synthesised. It was found that 4 exists in a carbonyl form, whereas 5 and 6 the hydroxy forms were the major tautomers
- Skramstad, Jan,Lunde, Andreas,Hope, Hakon,Bjornstad, Vidar,Froyen, Paul
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p. 1453 - 1458
(2007/10/03)
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- Mild chlorination of aromatic compounds with tin(IV) chloride and lead tetraacetate
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SnCl4/Pb(OAc)4 acts as a safe source of Cl2 for the chlorination of aromatic compounds. A variety of aromatic compounds are effectively chlorinated with SnCl4/Pb(OAc)4 under mild conditions. The mixture is a selective chlorinating agent, particularly with polyalkylbenzenes, polycyclic aromatic compounds and anisoles.
- Muathen, Hussni A.
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p. 8863 - 8866
(2007/10/03)
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- Biphasic Electrophilic Halogenation of Activated Aromatics and Heteroaromatics with N-Halosuccinimides Catalyzed by Perchloric Acid
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Catalytic amounts of 70percent perchloric acid (0.1 - 10, mostly 0.1 - 1, mol percent, based on substrate) initiate the regioselective halogenation of activated aromatics and heteroaromatics with N-halosuccinimide (NXS, X = Cl or Br) in two-phase solid-liquid systems (NXS/hexane or NXS/CCl4) at room temperature to give ring-halogenated products in high yields.For example, thiophene is transformed to 2-halo or 2,5-dihalo derivatives (yield 82-98percent) using 1 or 2 equiv of NXS, respectively.Unsymmetrical 2,5-dihalothiophenes are obtained in 70-82percent yield by reacting 2-halothiophenes with an appropriate NXS.The reaction of 3-bromothiophene with NBS affords 2,3-dibromothiophene in 93-99percent yield. 1,3-Dimethoxybenzene and 2,3-dimethylanisole are halogenated regiospecifically at the 4-position to give the corresponding products in 81-94percent yield.
- Goldberg, Yuri,Alper, Howard
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p. 3072 - 3075
(2007/10/02)
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- COMPOSITION OF REACTION MIXTURES IN THE OXIDATIVE CHLORINATION OF THIOPHENE IN THE SYSTEM HYDROGEN PEROXIDE - HYDROCHLORIC ACID
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The chlorination of thiophene in the system hydrogen peroxide-hydrochloric acid was investigated in order to find the conditions under which mixtures of thiophene and 2-chlorothiophene can be obtained with a relatively high content of chlorothiophene but
- Rudakova, N. I.,Anufrieva, O. V.,Smirnova, E. A.
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p. 1887 - 1890
(2007/10/02)
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