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Synthesis method of(R)-2-[4-(4-cyano-2-fluorophenoxy)phenoxy] propionic acid

A technology of fluorophenoxy and synthesis method, which is applied in the field of synthesis of -2-[4-phenoxy]propionic acid, can solve the problems of low conversion rate, high pressure of three wastes treatment, poor product quality, etc., and achieve reaction yield The effect of high efficiency, reduced raw material cost, and high atom utilization

Active Publication Date: 2019-12-13
湖南速博生物技术有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] This method has the following common problems in the synthesis of intermediate (R)-2-(4-hydroxyphenoxy)propionic acid: due to the easy oxidation of hydroquinone and the difficulty in separating it from products and by-products, the product quality is poor, and in EP352168 mentioned the use of hydroquinone and ( S )-2-chloropropionic acid methyl ester preparation ( R )-2-(4-Hydroxyphenoxy)propanoic acid, when hydroquinone is over-alkylated to form a bis-etherification by-product and hydroquinone is oxidized to produce a dark by-product; the formation of a bis-ether by-product cannot be avoided , the bis-ether by-product is positively correlated with the single-pass conversion rate, so at present the industry adopts a method with a low conversion rate to reduce the by-product of the bis-ether The content of hydroquinone is less than 0.1%; a large amount of inorganic alkali is used in the reaction process, resulting in a large amount of phenol-containing high-salt wastewater, and the pressure on the treatment of three wastes is high

Method used

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  • Synthesis method of(R)-2-[4-(4-cyano-2-fluorophenoxy)phenoxy] propionic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Intermediate I ( R )-2-(4-chlorophenoxy) propionic acid preparation: add 256 g water, 128 g p-chlorophenol and 80 g sodium hydroxide to a 1000ml three-necked flask, stir at 60°C for 0.5 h, then slowly add 122 g ( S)-Methyl 2-chloropropionate, keep warm for 4 h after the dropwise addition, cool down to room temperature, adjust the pH to 1 with concentrated hydrochloric acid to precipitate a solid, filter and dry to obtain intermediate I ( R )-2-(4-hydroxyphenoxy)propionic acid 178.5 g, content 98.1% (LC external standard method), yield 87.7%.

[0015] ( R )-2-[4-(4-cyano-2-fluorophenoxy) phenoxy] propionic acid preparation: add 400g DMF and 137 g 3-fluoro-4-hydroxybenzonitrile in a 2000ml three-necked flask, stir until Uniformly, then add 276 g of potassium carbonate in batches, after the end, raise the temperature to 90 ° C for 1 h, add 200 g of intermediate I to the system, after the addition, raise the temperature to 110 ° C for 10 h, then remove DMF by negative pre...

Embodiment 2

[0017] Intermediate I ( R )-2-(4-chlorophenoxy) propionic acid preparation: add 256 g water, 128 g p-chlorophenol and 120 g sodium hydroxide to a 1000ml three-necked flask, stir at 60°C for 0.5 h, then slowly add 146.5 g ( S )-methyl 2-chloropropionate, keep warm for 4 h after the dropwise addition, cool down to room temperature, adjust the pH to 1 with concentrated hydrochloric acid, and filter and dry the precipitated solid to obtain 183.5 g of intermediate I, with a content of 99.1% (LC external standard method), the yield was 91.0%.

[0018] ( R )-2-[4-(4-cyano-2-fluorophenoxy) phenoxy] propionic acid preparation: add 400 gDMF and 164.5 g 3-fluoro-4-hydroxybenzonitrile in a 2000ml three-necked flask, stir until Uniformly, then add 331.2 g of potassium carbonate in batches, after the end, raise the temperature to 90 ° C for 1 h, add 200 g of intermediate I to the system, after the addition, raise the temperature to 110 ° C and keep it for 10 h, then remove DMF by negative...

Embodiment 3

[0020] Intermediate I ( R )-2-(4-chlorophenoxy)propionic acid preparation: add 512 g water, 128 g p-chlorophenol and 120 g sodium hydroxide in a 1000ml three-necked flask, stir at 60°C for 0.5 h, then slowly add dropwise 122 g ( S )-Methyl 2-chloropropionate, keep warm for 4 hours after the dropwise addition, then cool down, adjust the pH to 1 with concentrated hydrochloric acid to precipitate a solid, filter and dry to obtain 182.5 g of intermediate Ⅰ, with a content of 98.2% (external standard method of liquid chromatography) , yield 89.7%.

[0021] ( R )-2-[4-(4-cyano-2-fluorophenoxy) phenoxy] propionic acid preparation: add 400 gDMF and 164.5 g 3-fluoro-4-hydroxybenzonitrile in a 2000ml three-necked flask, stir until Uniformly, then add 331.2 g of potassium carbonate in batches, after the end, raise the temperature to 90 ° C for 1 h, add 200 g of intermediate I to the system, after the addition, raise the temperature to 120 ° C and keep it for 10 h, then remove DMF by ne...

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Abstract

The invention discloses a method for synthesizing cyhalofop butyl intermediate(R)-2-[4-(4-cyano-2-fluorophenoxy)phenoxy] propionic acid.(S)-2-chloropropionic acid methyl ester and p-chlorophenol are used as raw materials, an etherification reaction is performed under an alkaline condition to generate(R)-2-(4-hydroxyphenoxy)propionic acid, and the etherification product and 3-fluoro-4-hydroxybenzonitrile generate the(R)-2-[4-(4-cyano-2-fluorophenoxy)phenoxy] propionic acid under the action of an acid-binding agent. According to the method, the problems of serious excessive hydroquinone servingas a raw material, massive use of an inorganic base and generation of dietherification byproducts in synthesis are avoided. The method is high in atom utilization rate, high in reaction yield and lowin production cost.

Description

technical field [0001] The present invention relates to a ( R )-2-[4-(4-cyano-2-fluorophenoxy)phenoxy]propionic acid synthesis method. Background technique [0002] Cyhalofop-ethyl is a special herbicide for paddy fields first developed by Dow AgroSciences Company in 1987 and introduced to the market in 1992. It is a kind of herbicide with high efficiency, low toxicity and high selectivity. agent, low residue, good environmental compatibility. Chemical Name: ( R )-Butyl 2-[4-(4-cyano-2-fluorophenoxy)phenoxy]propionate. The key intermediate ( R )-2-[4-(4-cyano-2-fluorophenoxy)phenoxy]propanoic acid. [0003] At present, the domestic and foreign ( R )-2-[4-(4-cyano-2-fluorophenoxy) phenoxy] propionic acid preparation method is mainly based on ( S )-2-methyl chloropropionate and hydroquinone are raw materials, and etherification reaction is carried out under alkaline conditions to generate etherification product ( R )-2-(4-hydroxyphenoxy group) propionic acid, etherific...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C253/30C07C255/54C07C51/09C07C59/70
CPCC07C253/30C07C51/09C07B2200/07C07C59/70C07C255/54
Inventor 陈三龙胡志彬王宇杨紫冬杨彬刘鹏吴宏霞
Owner 湖南速博生物技术有限公司
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