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Preparation method of 2,3,4,5-tetrafluorobenzoyl chloride

A technology of tetrafluorobenzoyl chloride and tetrafluorophthalic anhydride, which is applied in 2 fields, can solve the problems of high cost, complex process, low yield, etc., and achieve the goal of reducing raw material cost, reducing operation amount and improving yield Effect

Inactive Publication Date: 2012-08-08
浙江沙星医药化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The present invention proposes a preparation method of 2,3,4,5-tetrafluorobenzoyl chloride, which solves the problems of complex process, low yield and high cost in the prior art

Method used

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  • Preparation method of 2,3,4,5-tetrafluorobenzoyl chloride
  • Preparation method of 2,3,4,5-tetrafluorobenzoyl chloride

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Embodiment 1

[0041] A preparation method of 2,3,4,5-tetrafluorobenzoyl chloride, comprising:

[0042] (1) Synthesis of N-methyl-3,4,5,6-tetrafluorophthalimide

[0043] In a 1000ml glass flask equipped with a thermometer, a water separator, a reflux condenser, and a mechanical stirrer, add 125g (0.437mol) of 3,4,5,6-tetrachlorophthalic anhydride, 200g of toluene, and 500g of sulfolane in sequence , 37.3 g (0.481 mol) of 40% aqueous methylamine solution was heated to reflux, and the moisture in the reaction was separated. After the moisture is exhausted, the reflux is maintained for 2 hours. The toluene was distilled off under reduced pressure, and the inner temperature was controlled below 80°C until almost no distillate was distilled out. Then 145 g (2.5 mol) of potassium fluoride was added, and the temperature was raised to 180° C. to react for 10 hours. After the reaction was completed, the sulfolane and the product were distilled off under reduced pressure, and then the distilled liq...

Embodiment 2

[0050] (1) Change the sulfolane in step (1) of Example 1 to dimethyl sulfoxide, and the rest are the same as in step (1). After the treatment, 92.2 g (0.395 mol) of white solid was obtained, yield: 90.5%. Melting point: 158~161℃.

[0051] (2) In a 1000ml glass flask equipped with a thermometer, a water separator, a reflux condenser, and a mechanical stirrer, add 250g of water, 80g (0.34mol) of the product of the above step (1), and slowly add a concentration of 50% 250g of sulfuric acid aqueous solution, allow it to heat up naturally. After the addition, the temperature was raised to 110° C., and the reaction was carried out for 15 hours. The conversion rate was 100% as detected by the liquid phase. After the reaction, cool down to 10-15°C, and some materials will precipitate out, filter and rinse with cold water. An off-white solid was obtained.

[0052] (3) Synthesis of 2,3,4,5-tetrafluorobenzoic acid

[0053] In a 1000ml glass flask equipped with a thermometer, a water ...

Embodiment 3

[0056] (1) Change the sulfolane in embodiment 1 step (1) into N, N-dimethylformamide, when 3,4,5,6-tetrachlorophthalic anhydride is 125g (0.437mol), The molar ratio of 3,4,5,6-tetrachlorophthalic anhydride to methylamine aqueous solution was adjusted to 1:1.5, and the rest was the same as step (1). After treatment, a white solid was obtained.

[0057] (2) in the 1000ml glass flask that thermometer, water separator, reflux condenser, mechanical stirrer are housed, add 100g water, product 80g (0.34mol) of above-mentioned steps (1), slowly add 250g of the vitriol oil, Let it warm up naturally. After the addition, the temperature was raised to 150° C., and the reaction was carried out for 5 hours, and the conversion rate was 100% as detected by the liquid phase. After the reaction, cool down to 10-15°C, and some materials will precipitate out, filter and rinse with cold water. An off-white solid was obtained.

[0058] (3) Synthesis of 2,3,4,5-tetrafluorobenzoic acid

[0059] I...

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Abstract

The invention relates to a preparation method of 2,3,4,5-tetrafluorobenzoyl chloride. The preparation method comprises the following steps: carrying out a condensation reaction on raw materials of 3,4,5,6-tetrafluorophthalic anhydride and methylamine; fluorinating; hydrolyzing; decarboxylating; and chlorizing. An aqueous solution of methylamine is adopted as the raw material to substitute aniline which has a high price in the invention, so the raw material cost is obviously reduced. A solvent used in the fluorination reaction is added ahead of time, so a product can be distilled off together with the solvent after ending the fluorination reaction without separating a condensation product, and a fluorinated product can be obtained through elutriation. A byproduct potassium chloride can be recovered, so product benefits are improved, and the environmental pollution is obviously reduced, thereby the preparation method is suitable for industrialized production.

Description

technical field [0001] The invention relates to the technical field of pharmaceutical intermediates, in particular to a preparation method of 2,3,4,5-tetrafluorobenzoyl chloride. Background technique [0002] 2,3,4,5-Benzoyl chloride is an important intermediate in the synthesis of chemical raw materials, which can be used to produce ofloxacin or levofloxacin. [0003] In the existing production technology, as proposed in US5047553, aniline is used as raw material to react with 3,4,5,6-tetrachlorophthalic anhydride to obtain the imidized product of N-phenyl, and then imidized After the product is separated, it is put into the fluorination reaction. The process uses more expensive aniline as a raw material. At the same time, the product must be separated before the next step of reaction, which increases the amount of operation and reduces the yield. cause an increase in cost. [0004] Proposed in EP259663 is the fluorination reaction with sulfolane as a solvent. After the r...

Claims

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Application Information

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IPC IPC(8): C07C63/70C07C51/60
Inventor 王文秀王瑜
Owner 浙江沙星医药化工有限公司
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