- Preparation method of chlorobenzene
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The present invention relates to the field of chlorination, and discloses a preparation method of chlorobenzene, which comprises that chlorine gas and a compound having a structure represented by a formula (1) are subjected to a contact reaction in an inert halogenated hydrocarbon solvent to obtain chlorobenzene having a structure represented by a formula (2), wherein in the formula, R represents a C1-6 alkyl group. The method disclosed by the invention is simple to operate, high in yield, few in three wastes and very suitable for industrial production.
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Paragraph 0037-0054
(2021/06/22)
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- Efficient halogenation synthesis method of aryl halide
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The invention discloses an efficient halogenation synthesis method of aryl halide. The method comprises the following step: in the presence of a catalyst (sulfoxide or oxynitride), a halogenation reagent and a solvent, carrying out a halogenation reaction on an aromatic ring compound to obtain the aryl halide. According to the present invention, in the presence of a catalyst (sulfoxide or nitrogenoxide), a halogenation reagent and a solvent, the aromatic ring is subjected to an efficient halogenation reaction, such that the very useful aryl halide can be obtained with high activity and high selectivity; and by adopting the method disclosed by the invention, aryl halides can be efficiently synthesized, and the method has a wide application prospect in actual production.
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Paragraph 0164-0168
(2021/03/31)
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- Iron(III)-Catalyzed Chlorination of Activated Arenes
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A general and regioselective method for the chlorination of activated arenes has been developed. The transformation uses iron(III) triflimide as a powerful Lewis acid for the activation of N-chlorosuccinimide and the subsequent chlorination of a wide range of anisole, aniline, acetanilide, and phenol derivatives. The reaction was utilized for the late-stage mono- and dichlorination of a range of target compounds such as the natural product nitrofungin, the antibacterial agent chloroxylenol, and the herbicide chloroxynil. The facile nature of this transformation was demonstrated with the development of one-pot, tandem, iron-catalyzed dihalogenation processes allowing highly regioselective formation of different carbon-halogen bonds. The synthetic utility of the resulting dihalogenated aryl compounds as building blocks was established with the synthesis of natural products and pharmaceutically relevant targets.
- Mostafa, Mohamed A. B.,Bowley, Rosalind M.,Racys, Daugirdas T.,Henry, Martyn C.,Sutherland, Andrew
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p. 7529 - 7537
(2017/07/26)
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- Selective Halogenation Using an Aniline Catalyst
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Electrophilic halogenation is used to produce a wide variety of halogenated compounds. Previously reported methods have been developed mainly using a reagent-based approach. Unfortunately, a suitable "catalytic" process for halogen transfer reactions has yet to be achieved. In this study, arylamines have been found to generate an N-halo arylamine intermediate, which acts as a highly reactive but selective catalytic electrophilic halogen source. A wide variety of heteroaromatic and aromatic compounds are halogenated using commercially available N-halosuccinimides, for example, NCS, NBS, and NIS, with good to excellent yields and with very high selectivity. In the case of unactivated double bonds, allylic chlorides are obtained under chlorination conditions, whereas bromocyclization occurs for polyolefin. The reactivity of the catalyst can be tuned by varying the electronic properties of the arene moiety of catalyst.
- Samanta, Ramesh C.,Yamamoto, Hisashi
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supporting information
p. 11976 - 11979
(2015/08/18)
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- Synthesis of deuterated benzopyran derivatives as selective COX-2 inhibitors with improved pharmacokinetic properties
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We designed a series of specifically deuterated benzopyran analogues as new COX-2 inhibitors with the aim of improving their pharmacokinetic properties. As expected, the deuterated compounds retained potency and selectivity for COX-2. The new molecules possess improved pharmacokinetic profiles in rats compared to their nondeuterated congeners. Most importantly, the new compounds showed pharmacodynamic efficacy in several murine models of inflammation and pain. The benzopyran derivatives were separated into their enantiomers, and the activity was found to reside with the S-isomers. To streamline the synthesis of the desired S-isomers, an organocatalytic asymmetric domino oxa-Michael/aldol condensation reaction was developed for their preparation.
- Zhang, Yanmei,Tortorella, Micky D.,Wang, Yican,Liu, Jianqi,Tu, Zhengchao,Liu, Xiaorong,Bai, Yang,Wen, Dingsheng,Lu, Xin,Lu, Yongzhi,Talley, John J.
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p. 1162 - 1166
(2014/12/10)
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- Kaolin-assisted Aromatic Chlorination and Bromination
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Moist kaolin catalyses the regioselective and high-yielding chlorination and bromination of C6H5OR (R = C1-C8 alkyl. Bu1, allyl, cyclohexyl, benzyl) to 4-XC6H4OR (X = Cl and Br, respectively) with NaCl02 and Mn(acac)3 in CH2Cl2 in the absence and presence of NaBr, respectively, under mild and neutral conditions.
- Hirano, Masao,Monobe, Hiroyuki,Yakabe, Shigetaka,Morimoto, Takashi
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p. 662 - 663
(2007/10/03)
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- Selective aromatic chlorination of activated arenes with sodium chlorite, (salen)manganese(III) complex, and alumina in dichloromethane
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The reaction of alkyl phenyl ethers with sodium chlorite in dichloromethane in the presence of a (salen)manganese(III) complex and alumina preloaded with a small amount of water afforded monochlorination products with unusually high para selectivities under mild conditions. The NaClO2-based biphasic system can also be successfully used for the regioselective monochlorination of substituted anisoles and polymethoxybenzenes.
- Hirano,Yakabe,Monobe,Morimoto
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p. 1905 - 1912
(2007/10/03)
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- Facile Synthesis of Chloro-substituted Aromatic Ethers by Use of Benzyltrimethylammonium Tetrachloroiodate
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The reaction of aromatic ethers with a calculated amount of benzyltrimethylammonium tetrachloroiodate in acetic acid (or dichloromethane) under mild conditions gave, selectively, the objective chloro-substituted aromatic ethers in good yields.
- Kajigaeshi, Shoji,Shinmasu, Youichi,Fujisaki, Shizuo,Kakinami, Takaaki
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p. 415 - 418
(2007/10/02)
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- Aldose reductase inhibiting 5-(2-alkoxyphenyl) thiazolidinediones
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A series of 5-(2-alkoxyphenyl)thiazolidinediones and pharmaceutically acceptable salts thereof useful as hypoglycemic agents, aldose reductase inhibitors and as therapeutic agents for the treatment of chronic diabetic complications; intermediates therefore; and process for preparation of said compounds.
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- PHENYLATION CATIONIQUE DU CHLORO-4 ANISOLE, ETUDE DE LA MIGRATION DU CHLORE ET DU PHENYLE DANS LES CATIONS IPSO-ARENIUM.
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The phenyl cations obtained from the thermolysis of benzenediazonium tetrafluoroborate react with 4-chlroanisole to give, in addition to phenylation products at position 2 and 3, 2-chloro-4-methoxybiphenyl.The latter is formed by the attack of C6H5(1+) ipso to the chlorine followed by 1,2 migration of the halogen.This rearrangement is totally suppressed in nucleophilic solvents such as dimethylsulfoxide, whereas it is important in heterogeneous conditions.The ability of DMSO to trap the ipso-arenium ions has provided indirect evidence for the attack of C6H5(1+) ipso to the methoxy group. 1-2 migration of the phenyl group has been observed in arenium ions formed by attack of C6H5(1+) ipso to the chlorine and ipso to the methoxy group. 4-methoxybiphenyl and 2,4-dichloroanisole have not been detected by G L C so that dechlorophenylation of 4-chloroanisole must be negligible.
- Pilski, J.,Court, J.,Eustathopoulos, H.,Bonnier, J. M.
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p. 4331 - 4338
(2007/10/02)
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