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Preparation method of Quizalofop-p-ethyl with high optical content

A technology of quizalofop-p-p-p and optics, which is applied in the field of preparation of quizalofop-p-p-p-p-p-p-p-p-p-p-p-p, which can solve the problems of high toxicity, low yield, and large environmental impact of sulfuric acid esters.

Active Publication Date: 2010-08-04
NUTRICHEM LAB CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, sulfuric acid esters are highly toxic and carcinogenic, and have a great impact on the environment
At the same time, the synthesis of halopropionic acid needs to use L-lactic acid as raw material for SN 2 Obtained by substitution reaction, racemization is unavoidable in this process, and the operation is cumbersome; or (VII) is made into acid chloride and then reacted with ethanol to obtain the product, but the yield is low (53%, US4629493)

Method used

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  • Preparation method of Quizalofop-p-ethyl with high optical content
  • Preparation method of Quizalofop-p-ethyl with high optical content
  • Preparation method of Quizalofop-p-ethyl with high optical content

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 2

[0031] Example 2 Prepare quizalofop-p-ethyl with petroleum ether at 60°C-90°C as solvent

[0032] Under a nitrogen atmosphere, take 60mL of petroleum ether at 60°C-90°C and place it in a 100mL four-neck flask, add 0.2g of triethylamine, 1.0g (11mmol) of 200-250mesh sodium bicarbonate, 1.5g (5.4 mmol) 6-chloro-2-(4-hydroxyphenoxy) quinoline, 1.9g (7.0mmol) S(-) ethyl p-toluenesulfonyl lactate, reflux for 7h. Cool down to 55°C, add 30g of water to wash twice, let stand to separate the liquid, separate the lower aqueous phase, and extract the aqueous phase with petroleum ether twice, each time with an amount of 20mL. Combine the organic phases, add 0.5 g of activated carbon, and keep warm at 65°C-75°C for 1 hour. Suction filtration while it was hot, and the filtrate was precipitated under negative pressure to obtain 2.0 g of crude oily product.

[0033]15 g of absolute ethanol was added to the crude product for recrystallization to obtain 1.8 g of light yellow crystals with a p...

Embodiment 3

[0035] Embodiment 3 takes naphtha as solvent preparation quizalofop-p-ethyl

[0036] Under a nitrogen atmosphere, take 50 mL of naphtha and place it in a 100 mL dry four-necked flask, add 4.3 g (12.9 mmol) of strontium carbonate of 200 mesh to 300 mesh, 3.0 g (11 mmol) of 6-chloro-2-(4 -Hydroxyphenoxy)quinoxaline, 3.3g (12mmol) S(-) ethyl p-toluenesulfonyl lactate. Heat to 100°C-105°C, keep the reaction for 8h, cool down to 90°C, add 20g of water and stir for 0.5h, let stand to separate layers, add 1g of activated carbon to the organic phase, keep stirring at 80°C-85°C for 1h. Suction filtration while it was hot, the filtrate was cooled to below 10°C, filtered, the filter cake was rinsed with cold toluene and ethanol, and dried to obtain 3.5 g of light yellow crystals with a yield of 85%. [α] D20 = +35.0, enantiomeric ratio R / S = 98.7 / 1.3 (optical purity 97.4% e.e.). Analysis conditions: chiral column: Chiralpak AS-H, 254nm; mobile phase: n-hexane / isopropanol=98 / 2).

Embodiment 4

[0037] Embodiment 4 prepares quizalofop-p-ethyl by reclaiming naphtha as solvent

[0038] Under a nitrogen atmosphere, take 45mL of the reclaimed naphtha in Example 3 and place it in a 100mL four-neck flask, add 1.5g (11mmol) of potassium carbonate, 2.5g (9mmol) of 6-chloro-2-(4-hydroxyl Phenoxy) quinoline, 2.7g (10mmol) S (-) ethyl p-toluenesulfonyl lactate. At 100°C-105°C, keep the reaction for 6h. Cool down to 90°C, add 20g of water and stir for 0.5h, let stand to separate layers, add 1.2g of activated carbon to the organic phase, keep stirring at 80°C-85°C for 1h. Suction filtration while it was hot, the filtrate was cooled to below 10°C, filtered, the filter cake was rinsed with cold toluene and ethanol, and dried to obtain 3.0 g of light yellow crystals with a yield of 88%. [α] D20 = +34.9, enantiomeric ratio R / S = 98.6 / 1.4 (optical purity 97.2% e.e.).

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Abstract

The invention relates to a preparation method of Quizalofop-p-ethyl with high optical content. In the method, 6-chorine-(4-hydroxyl group phenoxyl) quinoxaline and S(-)p-toluenesulfonyl ethyl lactate are reacted in non-polar organic solvent for 4-8h under the temperature of 60-150 DEG C with metal carbonate of 100-800mesh as the catalyst. The optical antimer proportion of the Quizalofop-p-ethyl prepared by the method R:S is more than 98.5:1.5, which is suitable for industrial mass production, is easy for operation and low in cost.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a preparation method of quizalofop-p-ethyl with high optical content. Background technique [0002] Quizalofop-p-ethyl (quizalofop-P-ethyl), has another name called quizalofop-p-ethyl, is the aryloxyphenoxycarboxylic acid herbicide (EP-A-3004770, US-A-4629493, US-A-4629493, GB2126580.Heterocyclic ether type phenoxy fatty acid derivatives and herbicidal composition). The chemical name is (R)-2-[4-(6-chloroquinoxalin-2-yloxy)phenoxy] ethyl propionate, and its structural formula is as shown in (I): [0003] [0004] Quizalofop-p-ethyl is a highly selective treatment agent for dry field stems and leaves, and is an inhibitor of acetyl-CoA carboxylase (ACCase). It has a high degree of selectivity between grass weeds and dicotyledonous crops, and has a good control effect on grass weeds in broad-leaved crop fields. Compared with quizalofop-p-ethyl, it improves the spee...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D241/44A01N43/60A01P13/00
Inventor 乔振母灿先吴国林王俊罗进超路风奇黄民富王宝乾张宁
Owner NUTRICHEM LAB CO LTD
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