Synthetic method of cyhalofop-butyl active compound

A technology of cyhalofop-butyl and a synthesis method is applied in the field of synthesis of cyhalofop-butyl, which can solve the problems of difficult treatment, high cost of raw materials, and many three wastes, and achieves difficult racemization reaction, lower reaction temperature, and reaction selection. high sex effect

Active Publication Date: 2012-07-18
JIANGSU KUAIDA AGROCHEM
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  • Abstract
  • Description
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Problems solved by technology

These two kinds of methods all will be because of adopting raw material p-toluenesulfonyl chloride (this reaction first generates transition state intermediate...

Method used

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  • Synthetic method of cyhalofop-butyl active compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) Drop 500ml of ethylene glycol dimethyl ether into a 1000ml four-necked flask, (R)-4-hydroxyphenoxypropionic acid (I) 91g (0.5mol) [R / S=99 / 1], anhydrous Potassium carbonate 173.5g (2.5mol), polyethylene glycol-4002g, 3,4-difluorobenzonitrile (II) 69.5g (0.5mol). The temperature was raised to 85-90° C., and the reaction was kept for 6 hours, and the reaction was completed. Cool down to room temperature, filter, wash the filter cake with 100ml of ethylene glycol dimethyl ether, combine the filtrate and washing liquid, remove the solvent of ethylene glycol dimethyl ether under reduced pressure, add 300ml of water, and adjust the pH value to 1~2 with 10% hydrochloric acid 2. Add 500ml of toluene for extraction and separation, and dehydrate under reflux to obtain intermediate (R)-2-[4-(2-fluoro-4-nitrile)-phenoxy]-propionic acid (III) in toluene.

[0025] (2) Cool the (R)-2-[4-(2-fluoro-4-nitrile)-phenoxy]-propionic acid (III) toluene solution prepared above to 50°C, and...

Embodiment 2

[0028] (1) drop 500ml of dimethyl sulfoxide into a 1000ml four-necked flask, (R)-4-hydroxyphenoxypropionic acid (I) 91g (0.5mol) [R / S=99 / 1], anhydrous potassium carbonate 173.5g (2.5mol), 2g of tetrabutylammonium bromide, 69.5g (0.5mol) of 3,4-difluorobenzonitrile (II), heated up to 85°C-90°C, kept for 10 hours, and the reaction was completed. Cool down to room temperature, filter, wash the filter cake with 100ml dimethyl sulfoxide, combine the filtrate and washing liquid, remove the solvent dimethyl sulfoxide under reduced pressure, add 300ml of water, adjust the pH value to 1-2 with 10% hydrochloric acid, add 500ml Extract and separate with toluene, and dehydrate under reflux to obtain intermediate (R)-2-[4-(2-fluoro-4-nitrile)-phenoxy]-propionic acid (III) in toluene.

[0029] Photochemical and esterification reactions are the same as steps (2) and (3) in Example 1. The obtained cyhalofop-ethyl technical product was 150 g, the chemical content was 94.8% [R / S=97 / 3], and the...

Embodiment 3

[0031] (1) The synthesis of intermediate (R)-2-[4-(2-fluoro-4-nitrile)-phenoxy]-propionic acid (III) is the same as step (1) in Example 1.

[0032] (2) Add 1 g of catalyst DMF to the toluene solution of (R)-2-[4-(2-fluoro-4-nitrile)-phenoxy]-propionic acid (III) prepared above. Raise the temperature to 80°C-90°C, and pass through phosgene at a speed of 1200ml / min-1400ml / min. After passing through the light for 2 hours, pass through nitrogen to drive away the residual phosgene and hydrogen chloride gas to obtain the intermediate (R)- 2-[4-(2-Fluoro-4-cyano)-phenoxy]-propionyl chloride (IV) in toluene.

[0033] (3) Esterification is the same as step (3) in Example 1. The obtained cyhalofop-ethyl technical product was 151g, the chemical content was 96.8% [R / S=75 / 25], and the yield was 84.6% (calculated as 3,4-difluorobenzonitrile, the final percent). Appearance: white solid.

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Abstract

The invention discloses a synthetic method of a cyhalofop-butyl active compound. The method comprises the following steps of: undergoing a condensation reaction on (R)-4-hydroxyphenoxypropanoic acid and 3,4-difluorobenzonilyile serving as raw materials in an organic solvent under an alkaline catalysis condition to generate an intermediate, i.e., (R)-2-[4-(2-fluoro-4-nitrile)-phenoxyl]-propanoic acid; undergoing a photochemical reaction on the intermediate, i.e., (R)-2-[4-(2-fluoro-4-nitrile)-phenoxyl]-propanoic acid to generate an intermediate, i.e., (R)-2-[4-(2-fluoro-4-nitrile)-propionyl chloride; and undergoing a third step esterification reaction on the intermediate, i.e., (R)-2-[4-(2-fluoro-4-nitrile)-propionyl chloride and n-butyl alcohol to generate the cyhalofop-butyl active compound. The method has the advantages of simple process, low production cost, high chemical content, high optical purity and the like.

Description

technical field [0001] The invention relates to a method for synthesizing the original drug of cyhalofop-ethyl Background technique [0002] Cyhalofop-methyl, common name cyhalofop-butyl, other names Qianjin, cyhalofop-methyl, chemical name is (R)-2-[4-(4-cyano-2-fluorophenoxy)phenoxy] Butyl propionate. It is mainly used to control gramineous weeds, and has excellent selectivity to rice, etc. It is the only aryloxyphenoxypropionic acid herbicide with high safety to rice. Cyhalofop-ethyl is not only highly effective against various barnyardgrasses (including older barnyardgrass), but also can prevent and control Qianjinzi, crabgrass, double paspalum, foxtail, goosegrass, and kannada. [0003] According to domestic and foreign literature reports, there are two main synthetic routes of cyhalofop-ethyl at present: (1) the intermediate 4-oxo-(2'-fluoro- 4'-cyanophenoxy)benzenediol (A); (S)-butyl lactate reacts with p-toluenesulfonyl chloride to generate intermediate (S)-2-(4-m...

Claims

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Application Information

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IPC IPC(8): C07C255/54C07C253/30
Inventor 李梅芳赵亚新贾海峰杨翠云
Owner JIANGSU KUAIDA AGROCHEM
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