- Kilogram-Scale Synthesis of 2,4-Dichloro-5-fluorobenzoic Acid by Air Oxidation under the Continuous-Flow Process
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A continuous-flow process for the preparation of 2,4-dichloro-5-fluorobenzoic acid (BA) has been reported. We chose 2,4-dichloro-5-fluoroacetophenone (AP) as starting material and acetic acid as cosolvent to achieve the excellent results in the continuous-flow oxidization system. The nitric acid oxidation of BA is a violent exothermic reaction. However, the continuous-flow system includes advantages such as good mass and heat transfer to ensure the safety of the reaction. The influences of different factors, including reactant ratio, temperature, and residence time, were investigated based on single factor tests. The optimal reaction conditions were obtained, in which the yield reached up to 100%. Compared with the traditional tank reactor process, less nitric acid consumption, a higher product yield, less reacting time, being more environmental friendly, and process continuity ensuring higher operation safety are achieved in the continuous-flow system.
- Guo, Shaozheng,Yu, Zhiqun,Yu, Chuanming
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- 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 0051; 0053; 0055; 0057; 0060; 0062
(2020/08/22)
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- Preparation method of 2,4-dichloro-5-fluorobenzoyl chloride
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The invention discloses a preparation method of 2,4-dichloro-5-fluorobenzoyl chloride and belongs to the field of organic synthesis. The preparation method comprises the following steps: with 2,4-dichlorofluorbenzene as a raw material, performing friedel-crafts reaction and hydrolyzation to generate an intermediate, 2,4-dichloro-5-fluorobenzoyl chloride; and hydrolyzing, oxidizing and acylating a byproduct, biopolymer (III), generated by the reaction to obtain a final compound (II), wherein the total yield is 88% or above. According to the invention, the raw material conversation ratio is 80% or above, the defects that existing raw materials are hardly available, and the utilization ratio is low are overcome, resources are saved, the production cost is lowered, and the preparation method is simple to operate and easy for amplified production.
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Paragraph 0048-0050; 0057; 0063; 0069; 0075; 0081; 0087
(2017/09/18)
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- INHIBITORS OF STEAROYL-COA DESATURASE
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Provided herein are compounds of the formula (I): as well as pharmaceutically acceptable salts thereof, wherein the substituents are as those disclosed in the specification. These compounds, and the pharmaceutical compositions containing them, are useful for the treatment of diseases such as, for example, obesity.
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- A novel approach to Finafloxacin hydrochloride (BAY35-3377)
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Finafloxacin hydrochloride, an important clinical compound was synthesized by a novel synthetic approach. An active intermediate ethyl 7-chloro-8-cyano-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate 19 was prepared by a new route. The chiral (S,S′)-N-Boc 10 was derived from protected pyrrolidine and the absolute stereochemistry was established by X-ray analysis.
- Hong, Jian,Zhang, Zonghua,Lei, Huoxing,Cheng, Haiying,Hu, Yufang,Yang, Wanliang,Liang, Yinglin,Das, Debasis,Chen, Shu-Hui,Li, Ge
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p. 2525 - 2528
(2009/09/06)
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- Synthesis of some new fluorine containing 1,3,4-oxadiazole derivatives as potential antibacterial and anticancer agents
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The synthesis of a number of 1,3,4-oxadiazole derivatives have been described. 2,4-Dichloro-5-fluorobenzoyl hydrazine 1 on reacting with aromatic acids in presence of phosphorus oxychloride affords 2,5-disubstituted-1,3,4- oxadiazoles 2a-j. Aroyl hydrazine on reacting with carbon disulphide under basic condition gives oxadiazol-2-thione 3. Oxadiazol-2-thiones are regioselectively aminomethylated to give N-aminomethylated products 4a-c. Further, 3 undergoes regioselective alkylation on treating with alkyl/aroyl halides to give S-alkyl/aroyl products 5a-c. All the newly synthesized compounds have been screened for their antibacterial activity. Most of them show promising antibacterial activity. Also two out of nine compounds show anticancer activity in the primary anticancer assay.
- Bhat, K. Subrahmanya,Karthikeyan,Holla, B. Shivarama,Shetty, N. Suchetha
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p. 1765 - 1769
(2007/10/03)
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- Nitroarene catalyzed oxidation with sodium percarbonate or sodium perborate as the terminal oxidant
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A new catalytic oxidation method for the preparation of aromatic carboxylic acids from methyl aryl ketones is reported. The method is an alternative to the haloform reaction; it is benign and affords the desired product without production of any harmful side products. The catalytic cycle is based on the use of an electron-deficient nitroarene as catalyst with either of the two cheap and green oxidants sodium percarbonate or sodium perborate. The method gives a good yield (87%) and shows excellent selectivity when the model substrate (acetophenone) is oxidized. A series of benzoic acids of industrial interest were prepared by means of this method.
- Bj?rsvik, Hans-René,Merinero, José Angel Vedia,Liguori, Lucia
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p. 8615 - 8620
(2007/10/03)
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- Condensed pyrazole derivatives, process for producing the same and use thereof
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Novel pharmaceutical compositions for inhibiting Th2-selective immune response and pharmaceutical compositions for inhibiting cyclooxygenase comprising condensed pyrazole derivatives represented by the general formula (I): or salts thereof.
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- Synthesis of some new fluorine containing thiadiazolotriazinones as potential antibacterial agents
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2,4-dichloro-5-fluorophenyl, 4-fluoro-3-(Phenoxy)phenyl, 4-fluorophenyl groups are known pharmacophores and can be used in the synthesis of new biologically active molecules. Therefore, 4-amino-6-arylmethyl-3-mercapto-1,2,4- triazin5(4H)-ones 1 are conden
- Holla, B. Shivarama,Bhat, K. Subrahmanya,Shetty, N. Suchetha
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p. 2193 - 2199
(2007/10/03)
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- Process for the preparation of halogenated benzoic acids
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A process for the preparation of halogenated benzoic acids of formula (1): STR1 in which R1, R2, R3, R4 and R5 are hydrogen, fluorine, chlorine or bromine atoms or C1 -C6 -alkyl, C1 -C6 -alkoxy, nitro, cyano, trifluoromethyl, aidehyde, C1 -C4 -alkoxycarbonyl, -SO2 -C1 -C4 -alkyl, -SO2 -phenyl, -CONH2, -CON(C1 -C4 -alkyl)2, hydroxy, carboxy, -NH2 or -N(C1 -C4 - alkyl)2 groups, at least one of the substituents R1 -R5 being one of said halogen atoms, which comprises reacting 1 mol of a benzophenone, asymmetrically substituted on the benzene rings A and B, of general formula (2): STR2 in which R1 -R10 are as defined above for R1 -R5, with about 1 to about 10 mol of an oxidizing agent selected from the group comprising hydrogen peroxide, urea/hydrogen peroxide addition product, an alkali metal peroxide, ammonium, alkali metal or alkaline earth metal peroxodisulfates, pertungstates, perborates or percarbonates, ozone, alkyl- or aryl-percarboxylic acids, alkyl- or aryl-persulfonic acids or persulfuric acid, at temperatures from about -20° to about +100° C.
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- Process for the preparation of 2,4-dichloro-5-fluorobenzonitrile
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Process for the preparation of 2,4-dichloro-5-fluorobenzonitrile, by reacting 5-bromo-2,4-dichlorofluorobenzene with about 10 to about 300 mol % of copper(I) cyanide in the presence of about 10 to about 2,000 mol % of a polar aprotic solvent at temperatur
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