- Preparation method of 2,6-dibromoaniline
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The invention discloses a preparation method of 2,6-dibromoaniline. According to the method, 2,6-difluorobenzonitrile is used as an initial raw material, and the 2,6-dibromoaniline is synthesized through six steps of reactions including ammonolysis, diazotization bromination, re-ammonolysis, re-diazotization bromination, amidation and Hofmann degradation. The 2,6-dibromoaniline obtained in the process is a brown solid, and the purity of the 2,6-dibromoaniline is 98% or above.
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Paragraph 0018; 0025-0026; 0033
(2020/08/27)
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- Controlling charge-transfer properties through a microwave-assisted mono- or bis-annulation of dialkynyl-: N -(het)arylpyrroles
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A selective microwave-assisted mono- and bis-annulation of dialkynyl-N-(het)arylpyrrole derivatives is described. These polycyclic aromatic hydrocarbons (PAHs) have been photophysically and computationally characterized. The mono-annulated systems display interesting charge-transfer properties. By contrast, these properties vanish within the more conjugated bis-annulated compounds.
- Pierrat, Philippe,Hesse, Stéphanie,Cebrián, Cristina,Gros, Philippe C.
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p. 8568 - 8575
(2017/10/27)
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- The triple-bond metathesis of aryldiazonium salts: A prospect for dinitrogen cleavage
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The {N2} unit of aryldiazonium salts undergoes unusually facile triple-bond metathesis on treatment with molybdenum or tungsten alkylidyne ate complexes endowed with triphenylsilanolate ligands. The reaction transforms the alkylidyne unit into a nitrile and the aryldiazonium entity into an imido ligand on the metal center, as unambiguously confirmed by X-ray structure analysis of two representative examples. A tungsten nitride ate complex is shown to react analogously. Since the bonding situation of an aryldiazonium salt is similar to that of metal complexes with end-on-bound dinitrogen, in which {N2}→M σ donation is dominant and electron back donation minimal, the metathesis described herein is thought to be a conceptually novel strategy toward dinitrogen cleavage devoid of any redox steps and, therefore, orthogonal to the established methods. Who knows? Although the extrusion of molecular nitrogen from aryldiazonium salts is extremely facile, the metathetic cleavage of the N-N triple bond on treatment with alkylidyne ate complexes of molybdenum or tungsten is shown to be even faster. The analogy between [Ar-N2]+ and known [M-N2] complexes makes this process a potential model for dinitrogen cleavage devoid of any redox steps.
- Lackner, Aaron D.,Fürstner, Alois
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supporting information
p. 12814 - 12818
(2015/10/28)
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- A thermal stable α-diimine palladium catalyst for copolymerization of ethylene with functionalized olefins
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Copolymerization of polar monomers and olefins catalyzed by transition metal under mild conditions is a challenge. α-Diimine palladium complexes have great potential to catalyze the copolymerization of alkylacrylates and olefins. But they are prone to deactivation under mild conditions which limits their industrial application. A novel unsymmetrical α-diimine palladium complex with bulkier α-diimine ligand was provided in this paper. They were active in ethylene homopolymerization at 80 °C. At 50 °C they could produce ethylene/methylacrylate copolymer with moderate methylacrylate incorporation. The probable reason for the high thermal stability of these complexes was proposed.
- Pan, Huijie,Zhu, Liang,Li, Jiewei,Zang, Dandan,Fu, Zhisheng,Fan, Zhiqiang
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- Synthesis of pyrrolnitrin and related halogenated phenylpyrroles
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A general approach to halogenated arylpyrroles, including the antifungal natural product pyrrolnitrin, is described using newly synthesized halogenated pyrroles and 2,6-disubstituted nitrobenzenes or 2,6-disubstituted anilines.
- Morrison, Matthew D.,Hanthorn, Jason J.,Pratt, Derek A.
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supporting information; experimental part
p. 1051 - 1054
(2009/07/18)
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- Synthesis of N-and C-trimethylsilyl-substituded anililes
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N-Metallation of bromoanilines with ethylmagnesium bromide followed by a reaction with trimethylchlorosilane provided N-mono and N-bis(trimethylsilyl) bromoanilines depending on the structure of substrate. The metallation of bissilylated bromoanilines with butyllithium permitted the introduction of a trimethylsilyl substituent in the aromatic ring. Previously unknown 2-bromo-N,N-bis(trimethylsilyl)aniline, 2,6-dibromo-N-trimethylsilylaniline, 2,6-dibromo-N,N-bis(trimethylsilyl)aniline, 2-bromo-6-trimethylsilylaniline, 2-bromo-6-trimethylsilyl-N,N-bis(trimethylsilyl)aniline, 2-bromo-6- trimethylsilyl-N-trimethylsilylaniline, 2,4,6-tribromo-N-trimethylsilylaniline, and 2,4,6-tribromo-N,N-bis(trimethylsilyl)aniline were prepared. The structures of the compounds obtained were established by the chromato-mass spectrometry and 1H, 13C, and 29Si NMR spectroscopy.
- Storozhenko,Belyakova,Starikova,Nosova,Shulyat'eva,Frenkel',Pecherskii
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p. 892 - 897
(2008/12/20)
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- Mild and regioselective oxidative bromination of anilines using potassium bromide and sodium perborate
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The selective monobromination of various deactivated anilines using potassium bromide and sodium perborate as oxidant has been achieved. The use of ammonium molybdate as catalyst accelerates the rate of reaction but is not essential to obtain good yields and high selectivities. (C) 2000 Elsevier Science Ltd.
- Roche, Didier,Prasad, Kapa,Repic, Oljan,Blacklock, Thomas J.
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p. 2083 - 2085
(2007/10/03)
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- Liquid phase regioselective bromination of aromatic compounds over HZSM-5 catalyst
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A simple, efficient, regioselective and environmentally safe method for oxybromination of activated aromatics catalyzed by HZSM-5 is reported. The electrophilic substitution of bromine generated from KBr using HZSM-5 as a catalyst and H2O2 as an oxidant.
- Narender,Srinivasu,Kulkarni,Raghavan
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p. 3669 - 3675
(2007/10/03)
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- Magnetic susceptibilities of organic compounds: Part V - Influence of substituents on diamagnetic susceptibilities of disubstituted and trisubstituted benzenes
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The magnetic susceptibilities of a number of triads of isomeric disubstituted benzenes have been determined, choosing the compounds in such a way that the substituents are present in the following combinations: (i) two electron-releasing substituents, (ii) a halogeno and an electron-releasing substituent, (iii) a halogeno and an electron-attracting substituent, and (iv) two halogeno substituents.The data show that for types (i), (ii) and (iv), the ortho isomers have the highest magnetic susceptibilities, the susceptibilities decreasing in the order: ortho > meta > para; for type (iii), the meta-isomers have the highest susceptibilities, the susceptibilities decreasing in the order: meta > para > ortho.The diamagnetic susceptibilities of some isomeric trisubstituted benzenes have also been determined and the data reveal that the susceptibility is the highest where the crowding of substituents is the highest (1,2,3-isomer) and lowest where the substituents are staggered and least crowded (1,3,5-isomer).Another observation made in the case of trisubstituted benzene is the applicability of a principle of additivity of their diamagnetic susceptibilities.
- Baliah, V.,Jeyanthy, J. Judith Diana
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p. 472 - 476
(2007/10/02)
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- Syntheses and Physical Properties of Several Octiphenyls and a Septiphenyl
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Six symmetrical linear octiphenyls were synthesized by the Ullmann homo-coupling reaction of iodoquaterphenyl.Another satisfactory method for synthesizing octiphenyls is also described, i.e., a Kharash-type Grignard cross-coupling of biphenylylmagnesium bromide and diiodoquaterphenyl in the presence of bis(acetylacetonato)nickel(II).Moreover, m-septiphenyl was succesfully synthesized by deamination of the corresponding amino compound.Infrared studies of the polyphenyls indicated that the fine-structure bands in the regions of 770-810 and 870-915 cm-1 may be considered as indicators of the presence of consecutive m-phenylene rings, regardless of the existence of o- or p-phenylene rings.The ultraviolet spectra of the octiphenyls, which contain two kinds of linkages, showed absorption curves closely related to those of quaterphenyls corresponding to the structural units of the former compounds.The nuclear magnetic resonance spectra of the polyphenyls without an o-phenylene ring showed multiplet peaks due to the resonances of an isolated m-phenylene proton at the lowest field within a narrow region (δ 7.81-7.95).Hueckel molecular orbital calculations of the longest wavelength absorption bands of ten polyphenyls were carried out.The calculated and observed wavelengths were in rather good agreement except for the cases of three compounds.Keywords - Ullmann reaction; Ni-complex-catalyzed cross-coupling; octiphenyls; septiphenyls; IR; UV; NMR; MO; quaterphenyl derivatives; polyphenyls
- Ozasa, Shigeru,Fujioka, Yasuhiro,Fujiwara, Michiko,Ibuki, Eiichi
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p. 3210 - 3222
(2007/10/02)
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