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

An optical technology of quizalofop-p-ethyl is applied in the field of preparation of quizalofop-p-ethyl with high optical content, and can solve the problems of low yield, inevitable racemization, high toxicity of sulfate ester and the like

Active Publication Date: 2009-09-16
NUTRICHEM LAB CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

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 1

[0027] Example 1 Preparation of quizalofop-p-ethyl with petroleum ether at 90°C-120°C as solvent

[0028] Under the environment of blowing nitrogen gas, take 50 mL of petroleum ether at 90°C-120°C and place it in a 100mL four-necked bottle, add 0.1g of tetrabutylammonium bromide, 3.7g (26.7mmol) of 200-300mesh potassium carbonate, 6.2 g (22.3mmol) 6-chloro-2-(4-hydroxyphenoxy) quinoline, 6.8g (24.5mmol) S (-) ethyl p-toluenesulfonyl lactate, reflux reaction for 6h. Cool down to 60°C, add 30g of water to wash, let stand to separate the liquid, remove the lower aqueous phase, add 1g of activated carbon to the organic phase, keep warm at 65°C-75°C for 1h, filter while hot, and the filtrate is precipitated under negative pressure to obtain a crude oily product 8.3g.

[0029] 30 g of absolute ethanol was added to the crude product for recrystallization to obtain 7.4 g of light yellow crystals with a purity of 99% and a yield of 87%.

[0030] mp=76°C-77°C, [α] 20 =+35.1 (EtOH, c=...

Embodiment 2

[0031] Example 2 Preparation of 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 1h. 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 ...

Embodiment 3

[0035] Example 3 Using naphtha as a solvent to prepare quizalofop-p-ethyl

[0036] Under a nitrogen atmosphere, take 50 mL of naphtha and place it in a 100 mL dry four-neck 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).

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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 specifically relates to a preparation method of quizalofop-op with high optical content. Background technique [0002] Quizalofop-P-ethyl, also known as quizalofop-P-ethyl, is an aryloxyphenoxycarboxylic acid herbicide developed by Japan's Nissan Chemical Industry Company (EP-A-3004770, US-A-4629493, GB2126580.Heterocyclic ether type phenoxy fatty acidderivatives and herbicidal composition). The chemical name is (R)-2-[4-(6-chloroquinoxalin-2-yloxy)phenoxy]propionic acid ethyl ester, and its structural formula is as shown in (I): [0003] [0004] Quizalofop is a highly selective upland stem and leaf treatment agent and an inhibitor of acetyl-CoA carboxylase (ACCase). It has high selectivity between grass weeds and dicotyledonous crops, and has good control effect on grass weeds in broadleaf crop fields. Compared with Quizalofop, Quizalofop has increased the speed of being absorbed by p...

Claims

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Application Information

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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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