- Environment-friendly production process of 2, 4-dichloro-5-fluorobenzoyl chloride
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The present invention relates to the field of chemistry, and particularly provides a preparation method of 2, 4-dichloro-5-fluorobenzoyl chloride. According to the invention, dimerization by-productsof the 2, 4-dichloro-5-fluorobenzoyl chloride produced by a carbon tetrachloride method are subjected to alkaline hydrolysis under the action of a catalyst, then after acidification, the processed product reacts with trichloride generated by condensation of a main reaction to be converted into 2, 4-dichloro-5-fluorobenzoyl chloride, and the yield reaches over 99.8%.
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Paragraph 0063-0068
(2020/08/22)
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- Synthesis method of 2, 4-dichlorofluorobenzene
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The invention discloses a synthetic method of 2, 4-dichlorofluorobenzene. The method comprises the following steps: 1,2,4-trichlorobenzene is used as a raw material, a calix[6]arene and trimethylolpropane borate compound is used as a phase transfer catalyst, spray-dried potassium fluoride is used as a fluorinating agent, and the 2,4-dichlorofluorobenzene is produced through one step of reaction; herein, the molar ratio of trimethylolpropane borate to potassium fluoride is 1:10-1:20, preferably 1:15; the molar ratio of the potassium fluoride to the 1,2,4-trichlorobenzene is 1:1.1; the calix[6]arene is p-tert-butyl calix[6]arene; and the molar ratio of the p-tert-butyl calix[6]arene to the 1,2,4-trichlorobenzene is 0.001:1-0.05:1, preferably 0.02:1. By using the calixarene and trihydroxymethyl borate composite catalyst, the catalytic efficiency is greatly improved, and the product yield is as high as 92%. The boiling point of the 2,4-dichlorofluorobenzene is 168-169 DEG C, the boiling point of the raw material 1,2,4-trichlorobenzene is 214 DEG C, and the boiling point of the solvent sulfolane is 285 DEG C, so that the product is simple to separate and purify. The method has the advantages of one-step synthesis, short reaction route, avoidance of nitrification and high-temperature chlorination, safer synthesis process and suitability for industrial production.
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Paragraph 0030-0033
(2019/07/04)
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- Preparation method for fluoroquinolones intermediate 2,4-dichloro-5-fluorobenzoyl chloride
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The invention discloses a preparation method for fluoroquinolones intermediate 2,4-dichloro-5-fluorobenzoyl chloride, and belongs to the technical field of the pharmaceutical synthesis. Through changing a compound IV into a compound V* and raw material 2,4-dichlor fluorbenzene, easy explosive materials of hydrogen peroxide and the like are avoided from being used. The compound V*, through a one-step reaction, is changed into the compound 2,4-dichloro-5-fluorobenzoyl chloride. A synthesized product is higher in purity, a total yield of a two-step reaction is higher, the generated starting raw material 2,4-dichlor fluorbenzene can be recycled, and carboxylate (V*) is changed into acyl chloride (II), and hydrochloric acid is not generated, pollution can be reduced. The method is more superiorto an existing technology, capable of increasing a resource utilization rate, reducing a production risk, reducing production cost, and more suitable for industrial production.
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Paragraph 0054; 0055; 0057; 0058; 0060; 0061
(2019/05/20)
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- Synthetic method of ciprofloxacin intermediate 2,4-dichlorofluorobenzene
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The invention provides a synthetic method of a ciprofloxacin intermediate 2,4-dichlorofluorobenzene and specifically relates to the technical field of drug intermediates. The synthetic method comprises the following steps: S1, stirring 2,4-dichloroaniline hydrochloride and hydrochloric acid to form a paste, and cooling; S2, dissolving sodium nitrite in warm water, freezing to zero DEG C for standby, adding boric acid into 40% hydrofluoric acid, and freezing to zero DEG C for standby; S3, adding crushed ice into the paste, pouring a sodium nitrite solution, fully stirring, filtering reactants,cooling a filtrate to zero DEG C, pouring a fluoboric acid solution, separating out white crystal fluorboric diazonium salt, stirring, filtering out crystals and air-drying to obtain a crude product;and S4, heating fluorboric diazonium salt, thawing, decomposing, keeping stationary boiling for 0.5 h, washing, carrying out atmospheric distillation to obtain an orange-yellow distillate, drying andcarrying out fractional distillation, collecting a fraction of a certain temperature to obtain 2,4-dichlorofluorobenzene. The invention has the following advantages: raw materials are easily available; operation is safe; and the synthetic method is suitable for industrial production.
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Paragraph 0016-0036
(2018/11/26)
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- O-dichlorobenzene with a quinolone drugs for coproduction method of key intermediate
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The invention relates to the field of methods for preparing medicinal intermediates, in particular to the field of methods for preparing key intermediates of quinolone medicines, and develops a method for coproducing the key intermediates of the quinolone medicines by using o-dichlorobenzene as a raw material. The method comprises the following steps of: nitrifying the o-dichlorobenzene serving as the raw material, and performing distillation, purification and stepwise crystallization to obtain 2,3-dichloronitrobenzene and 3,4-dichloronitrobenzene; performing fluoridation on the 2,3-dichloronitrobenzene to obtain 3-chloro-2-fluoronitrobenzene, performing chlorination to obtain 2,6-dichlorofluorobenzene, performing nitration to obtain 1,3-dichloro-2-fluoro-4-nitrobenzene, and finally performing fluoridation to obtain 2,3,4-trifluoronitrobenzene; and performing fluoridation on the 2,3,4-trifluoronitrobenzene to obtain 3-chloro-4-fluoronitrobenzene, performing chlorination to obtain 1,3-dichloro-4-fluorobenzene, and finally performing acylation reaction on the 1,3-dichloro-4-fluorobenzene and acetylchloride to obtain 2,4-dichloro-5-fluoroacetophenone.
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- Continuous flow reactor for Balz-Schiemann reaction: A new procedure for the preparation of aromatic fluorides
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A facile and highly efficient procedure for the preparation of aromatic fluorides by Balz-Schiemann reaction via two continuous flow reactors has been set up. The continuous diazotization reactor was run at about 25 °C with residence times of 10-20 s, and the continuous fluorodediazoniation reactor was performed with a residence time of 1 min in high yields. The reaction times can be greatly reduced by increasing temperature and thereby taking advantage of superior mass and heat transfer of a continuous flow system.
- Yu, Zhi-Qun,Lv, Yan-Wen,Yu, Chuan-Ming,Su, Wei-Ke
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p. 1261 - 1263
(2013/03/14)
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- Synthesis of 2,4-dihalogenofluorobenzenes and their antimicrobial and antifungal activity studies
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The aim of this study was to synthesize and identify 2,4- dihalogenofluorobenzene (or trihalogenobenzene) derivatives by spectroscopic means, 1H-NMR and 19F-NMR. The 2,4-dihalofluorobenzene derivatives considered were 2,4-dichlorofluorobenzene (1), 2-bromo-4- chlorofluorobenzene (2), 2-iodo-4-chlorofluorobenzene(3), 2,5- dichlorofluorobenzene (4), 2-bromo-5-chlorofluorobenzene (5), 2-iodo-5-chlorofluorobenzene (6). The in vitro antibacterial and antifungal activities of trihalogenobenzene derivatives were studied against the bacteria Staphylococcus aureus ATCC 25923 Gram(+), Bacillus cereus ATCC 6633 Gram(+), Micrococcus flavus (clinical isolate) Gram(+), Morgenella morganii (clinical isolate) Gram(-), Escherichia coli ATCC 27853 Gram(-) and fungus Candida albicans (clinical isolate), obtained from the biology departments of the Pamukkale and Gazi Universities. The antibacterial and antifungal activities were measured by minimum inhibition concentration (MIC) method and the disc-diffusion method used to measure zone diameter against Gram-positive and Gram-negative bacteria and fungi. All these bacteria and fungi were studied against antibiotics to compare the zone diameters with the results from our treatments. Birkhaeuser 2007.
- Katircioglu, Hikmet,Logoglu, Elif,Tilki, Tahir,Oektemer, Atilla
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p. 205 - 212
(2008/12/21)
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- Preparation process of fluorine substituted aromatic compound
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A preparation process of a fluorine substituted aromatic compound comprising reacting an alkali metal or alkali earth metal salt of an aromatic compound having a hydroxy group with an organic fluorinating agent is disclosed. As a representative fluorinating agent, a bis-dialkylamino-difluoromethane compound, for example, 2,2′-difluoro-1,3-dimethylimidazolidine, is exemplified. According to the process, an industrially useful fluorinated aromatic compound, for example, a fluorobenzene, a fluorine substituted benzophenone, a fluorine substituted diarylsulfone can be prepared with ease in economy without specific equipment.
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- A new synthesis of aryl fluorides: The reaction of caesium fluoroxysulfate with arylboronic acids and derivatives
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The ipso fluorination of arylboronic acids and some derivatives with caesium fluoroxysulfate has been developed. The reaction proceeds with the wide range of functionalised aromatics and is strongly solvent dependent.
- Diorazio,Widdowson,Clough
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p. 8073 - 8088
(2007/10/02)
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- Photo-Rearrangement of Polychlorobenzenes meta-Migration of Chlorine Atom
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Several polychlorobenzenes were irradiated by ultraviolet light (254 nm) in acetonitrile and the products were determined by gas chromatography.In addition to the abstraction of hydrogen atom from the solvent, photo-isomerization was shown to proceed giving isomeric polychlorobenzenes one of which chlorine atoms migrated to meta to the original position.The meta-rearrangement was rationalized by an MNDO calculation on o-chlorophenyl free radical.
- Morisaki, Kenji,Miura, Yasuki,Abe, Kazuhisa,Hirota, Minoru,Nakada, Masahiro
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p. 1589 - 1592
(2007/10/02)
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