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Method for continuously synthesizing imazethapyr

A technique for forming imazethapyr from imazethapyr, which is applied in the field of synthesis of agricultural herbicide imazethapyr, can solve the problems of increasing economic cost, synthetic yield, unsatisfactory content, etc., and achieves the effect of simple and reasonable process route

Active Publication Date: 2014-01-22
JIANGSU CHANGQING AGROCHEMICAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the relatively economical and reasonable method for synthesizing imazethapyr in China is to use 2-amino-2,3-dimethylbutyramide and 5-ethyl-2,3-pyridine anhydride to synthesize, but the above-mentioned method has unsatisfactory synthesis yield and content. Defects, in order to increase the economic cost, need to be further improved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0007] Example 1 Dissolve 2-amino-2,3-dimethylbutyramide and sodium methoxide in toluene at 50:2 (weight ratio), and use a metering pump to mix the toluene liquid and 5-ethylpyridine-2,3-carboxylate Add diethyl acetate to the continuous reaction device at a ratio of 52:100 (weight ratio), the reaction temperature is 55°C, and the residence time is 12 hours. After the reaction, the reaction solution is continuously extracted. The pH of the water phase is 5, and the oil layer enters the thin-film evaporator and is distilled to obtain the original drug of imazethapyr, with a synthesis yield of 85% and a content of 97%.

example 2

[0008] Example 2 Add 100 grams of diethyl 5-ethylpyridine-2,3-carboxylate dropwise into 220 grams of sodium hydroxide solution in a three-necked flask, add the dropwise time for 1 hour, raise the temperature to 65°C, keep it warm for 1 hour, under negative pressure Remove ethanol-water, add 80 grams of hydrated 350 grams of tetrahydrofuran, control the temperature at 40°C, adjust the pH to 2 with 40% sulfuric acid, separate layers, distill the oil layer to remove tetrahydrofuran, add 89 grams of acetic anhydride and 38 grams of 4-picolin, React at room temperature for 1 hour, and distill under reduced pressure to obtain 5-ethylpyridine-2,3-carboxylic acid anhydride with a yield of 81%. Dissolve 5-ethylpyridine-2,3-carboxylic acid anhydride and 50 grams of 2-amino-2,3-dimethylbutanamide in toluene, stir at room temperature for 12 hours, add 5.5 grams of triethylamine, heat and reflux for dehydration for 2 After 1 hour, remove toluene under reduced pressure, add 200 grams of wat...

example 3

[0009] Example 3 Dissolve 2-amino-2,3-dimethylbutyramide and sodium methoxide in toluene at 50:1 (weight ratio), and use a metering pump to mix the toluene liquid and 5-ethylpyridine-2,3-carboxylate Diethyl diethyl ester was added to the continuous reaction device at a ratio of 51:100 (weight ratio), the reaction temperature was 55°C, and the residence time was 12 hours. After the reaction, the reaction solution was continuously extracted. The pH of the water phase is 5, and the oil layer enters the thin-film evaporator, and then distilled to obtain the original drug of imazethapyr, with a synthesis yield of 75% and a content of 97%.

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Abstract

The invention relates to a method for continuously synthesizing imazethapyr. 5-ethylpyridine-2,3-carboxylic acid diethyl ester and 2-amino-2,3-cimethylbutyramide serving as raw materials are continuously synthesized in the action of a catalyst sodium methoxide to prepare an imazethapyr active compound, wherein the weight ratio of 5-ethylpyridine-2,3-carboxylic acid diethyl ester to 2-amino-2,3-cimethylbutyramide to sodium methoxide is 100:50:2. The method for continuously synthesizing imazethapyr by utilizing 5-ethylpyridine-2,3-carboxylic acid diethyl ester and 2-amino-2,3-cimethylbutyramide is simple and reasonable in process flow, economical and practical; the imazethapyr with the synthesis yield of 85 percent and content of 97 percent can be obtained by virtue of the reasonable preparation and proper catalyst.

Description

technical field [0001] The invention relates to the synthesis technology of the agricultural herbicide imazethapyr. Background technique [0002] Imazethapyr is an imidazolinone herbicide, that is, a branched-chain amino acid biosynthesis inhibitor. The drug is absorbed through roots and leaves, and is transmitted to the meristem, hindering plant growth. Soybean can metabolize it quickly, so it has strong tolerance to the drug, and it is a selective herbicide in pre-emergence and early post-emergence. Control grass weeds and certain broad-leaved weeds in soybean fields and other legume fields such as barnyardgrass, golden dogtail, green dogtail, velvetleaf, amaranthus retrovertica, Chenopodium, etc. At present, the relatively economical and reasonable method for synthesizing imazethapyr in China is to use 2-amino-2,3-dimethylbutyramide and 5-ethyl-2,3-pyridine anhydride to synthesize, but the above-mentioned method has unsatisfactory synthesis yield and content. Defects, i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D401/04
CPCC07D401/04
Inventor 于国权丁华平王欣袁宇
Owner JIANGSU CHANGQING AGROCHEMICAL CO LTD