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Method for preparing 2-methoxy-4-trifluoromethyl-3-pyridinesulfonyl chloride

A technology of trifluoromethylpyridine and pyridinesulfonyl chloride, which is applied in the direction of organic chemistry, can solve the problems of unfavorable environmental protection, low safety factor, ether solution anesthesia, etc., and achieves the advantages of production safety, environmental protection and odor reduction The effect of sexual odor

Inactive Publication Date: 2018-09-21
CHANGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the existing preparation process of the key intermediate 2-methoxy-4-trifluoromethyl-3-pyridinesulfonyl chloride of acesulfame, in the group of preparing sulfonyl chloride, the diethyl ether solution of methyllithium and di Propyl disulfide reacts at low temperature to prepare thioether. The sulfide itself has a serious foul smell, which is not conducive to environmental protection, and the ether solution has the effect of anesthesia, so there is a big safety hazard in use.
The use of highly toxic gas chlorine in the process of preparing sulfonyl chloride from sulfide has high requirements for equipment and production operations, and the safety factor is low, which is not conducive to safe production and environmental protection

Method used

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  • Method for preparing 2-methoxy-4-trifluoromethyl-3-pyridinesulfonyl chloride
  • Method for preparing 2-methoxy-4-trifluoromethyl-3-pyridinesulfonyl chloride
  • Method for preparing 2-methoxy-4-trifluoromethyl-3-pyridinesulfonyl chloride

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Preparation of compound Ⅱ

[0033]

[0034] Add 2-chloro-4-trifluoromethylpyridine (10.0g, 0.055mol) into the reaction flask, and 10% sodium methoxide solution (30.0g, 0.055mmol) with a mass fraction of 10%, heat up and react at 55°C, GC tracked that the reaction of the raw materials was complete. After the reaction was completed, cool to room temperature, filter, recover methanol in vacuo, add water and dichloromethane to extract and separate layers, and concentrate the dichloromethane under reduced pressure to obtain 8.38 g of light yellow liquid with a yield of 86.1%. 1 H-NMR (300MHZ, CDCl 3 )δ8.23(d, J=3HZ, 1H, pyridine ring hydrogen), 6.99(d, J=6HZ, 1H, pyridine ring hydrogen), 6.88(s, 1H, pyridine ring hydrogen), 3.89(s, 3H, -OCH 3 ).

[0035] Preparation of compound Ⅲ

[0036]

[0037] Under nitrogen protection, add n-hexane (140ml), diisopropylamine (5.1g, 0.05mol) into the reaction flask, cool to -60°C and add dropwise 2.2M n-butyllithium cyclohexane ...

Embodiment 2

[0043] Preparation of Compound II:

[0044]

[0045] The raw material 2-chloro-4-trifluoromethylpyridine (18.5g, 0.102mol) was first added to the reaction flask, and 15% sodium methoxide solution (73.4g, 0.204mol) was slowly added, and after mixing, the temperature was raised to 60°C Reaction, GC tracking and analysis of raw materials After the reaction is complete, cool down to room temperature, obtain the filtrate by suction filtration, remove methanol under reduced pressure, add water and dichloromethane to extract and separate layers, and concentrate dichloromethane under reduced pressure to obtain 16.1 g of light yellow liquid. 89.2%.

[0046] Preparation of compound III:

[0047]

[0048]Under the protection of argon, in the three-necked flask, first add 250ml of tetrahydrofuran, add triethylamine (12.5g, 0.124mol) into the reaction flask, and then start to cool down to -50°C, add 2.2M n-butyllithium cyclohexane Add alkane solution (77.5ml, 0.171mol) slowly, afte...

Embodiment 3

[0053] Preparation of compound Ⅱ

[0054]

[0055] Add 2-chloro-4-trifluoromethylpyridine (45.5g, 0.251mol) in the reaction flask, after the mass fraction is 30% sodium methoxide solution (135.5g, 0.753mol) and mix well, heat up, at 65 Reaction at ℃, followed by GC until the raw material reacted completely, cooled to room temperature after the reaction, filtered, recovered methanol in vacuum, added water and dichloromethane to extract and separate layers, concentrated dichloromethane under reduced pressure to obtain 40.9 g of light yellow liquid, yield 92.1 %.

[0056] Preparation of compound Ⅲ

[0057]

[0058] Under nitrogen protection, add 2-methyltetrahydrofuran (380ml), n-propylamine (12.6g, 0.213mol) into a four-neck flask, cool to -40°C and add dropwise 2.2M n-butyllithium cyclohexane solution (116.4ml, 0.256mol), stirred for 1h, added dropwise 2-methoxy-4-trifluoromethylpyridine (37.8g, 0.213mol), reacted at -40°C for 3 hours, and added sulfur powder (8.2g, 0.2...

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Abstract

The invention provides a method for preparing 2-methoxy-4-trifluoromethyl-3-pyridinesulfonyl chloride, and belongs to the field of fine chemical engineering. The method comprises the following steps:2-chloro-4-trifluoromethylpyridine used as a starting material is methoxylated to obtain a 2-methoxy-4-trifluoromethyl-3-pyridine compound, the 2-methoxy-4-trifluoromethyl-3-pyridine compound reacts with sulfur powder under the action of butyllithium to prepare a 2-methoxy-3-mercapto-4-trifluoromethyl-3-pyridine compound, and the 2-methoxy-3-mercapto-4-trifluoromethyl-3-pyridine compound is chlorinated and oxidized to obtain the final product 2-methoxy-4-trifluoromethyl-3-pyridinesulfonyl chloride compound. The sulfur powder is used the preparation process of compound III, and thioether compounds are avoided, so odorous odor brought in the production process is eliminated, and environmental pollution is reduced. Hydrogen peroxide is adopted to carry out oxidation, thionyl chloride is adopted to carry out chlorination, and chlorine is avoided, so dangers in the preparation and synthesis process are effectively reduced, and the safety production coefficient is improved.

Description

Technical field: [0001] The invention belongs to the field of fine chemicals, and in particular relates to a preparation method of 2-methoxy-4-trifluoromethyl-3-pyridinesulfonyl chloride. Background technique: [0002] Pyrexsulam, commonly known as pyroxsulam in English, is a triazolopyrimidinesulfonamide herbicide developed by Dow AgroSciences. Grass and broadleaf weeds. It has excellent herbicidal effect on vicious gramineous weeds in wheat fields, such as A. japonica, ryegrass multiflora, wild oats, hard grass, etc., and has no interaction with fenoxaprop-ethyl and clodinafop-propargyl. At present, the acesulfame preparations registered in China include 7.5% water-dispersible granules (the trade name is preferred) and 4% dispersible oil suspension concentrates. [0003] [0004] In the existing preparation process of the key intermediate 2-methoxy-4-trifluoromethyl-3-pyridinesulfonyl chloride of acesulfame, in the group of preparing sulfonyl chloride, the diethyl eth...

Claims

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Application Information

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IPC IPC(8): C07D213/71
CPCC07D213/71
Inventor 徐德锋管静
Owner CHANGZHOU UNIV
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