Preparation method of 2-nitro-4-methylsulfonylbenzoic acid

A technology of thiamphenicol benzoic acid and alkyl thiamphenicol benzoate, applied in the field of preparation of 2-nitro-4-thiamphenicol benzoic acid, can solve the problem of poor oxygen reactivity, harsh reaction conditions, and easy pollution Environmental and other issues, to achieve the effect of simple post-processing steps and easy operation

Active Publication Date: 2021-12-17
NUTRICHEM LAB CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The nitro group and thiamphenyl group in the 2-nitro-4-thiamphenicol toluene molecule are strong electron-withdrawing groups, which makes the oxidation of its methyl group very difficult and requires relatively harsh reaction conditions. The current industrial production method is mixed acid oxidation method, the reaction temperature is high, the equipment is severely corroded, a large amount of waste acid is produced, and there are safety risks
Another process uses heavy metal oxidants such as dichromate and permanganate, which are easy to pollute the environment
If oxygen is used as the oxidant, the reaction conditions are generally harsh due to the poor reactivity of oxygen itself.

Method used

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  • Preparation method of 2-nitro-4-methylsulfonylbenzoic acid
  • Preparation method of 2-nitro-4-methylsulfonylbenzoic acid

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preparation example Construction

[0025] The invention provides a kind of preparation method of 2-nitro-4-thiamphenicol benzoic acid, the method comprises the following steps,

[0026] 1) In the presence of a base, in the presence of a catalyst and a catalyst ligand, 2-nitro-4-thiamphenicol chlorobenzene is coupled with carbon monoxide and an alcohol with 1-3 carbon atoms to obtain 2-nitro - Alkyl 4-thiamphenicol benzoate;

[0027] 2) the 2-nitro-4-thiamphenicol alkyl benzoate obtained in step 1) is hydrolyzed,

[0028] Wherein, the catalyst is one or more of palladium acetate, palladium chloride, palladium nitrate and copper acetate, and the catalyst ligand is triphenylphosphine, bisdiphenylphosphineethane, bisdiphenylphosphine One or more of propane, bis(diphenylphosphino)benzene, and bis(diphenylphosphino)yldimethylxanthene.

[0029] In the present invention, in the presence of a base, in the presence of a catalyst and a catalyst ligand, 2-nitro-4-thiamphenicol chlorobenzene is reacted with carbon monoxid...

preparation Embodiment 1

[0063] This example is used to illustrate the preparation of 2-nitro-4-thiamphenicol chlorobenzene

[0064] (1) Add 174.8 grams (1.5 moles) of chlorosulfonic acid, 8.8 grams (0.15 moles) of sodium chloride and 150 ml of 1,2-dichloroethane in sequence in the reaction flask; start stirring, heat, and raise the temperature to 55-60°C ; Then the 1,2-dichloroethane solution (1,2-dichloroethane 250ml) containing 79.8 grams of o-chloronitrobenzene (0.5 moles, 99%) was added dropwise to the above-mentioned mixed solution in 20 minutes medium; after the dropwise addition, keep warm for 5 hours, pour into 500ml ice-water mixture, stir, let stand, and separate the organic layer; dry the organic layer, and precipitate to obtain a light yellow solid 3-nitro-4-chloro Benzenesulfonyl chloride.

[0065] (2) Add 75.6 grams (0.6 moles) of anhydrous sodium sulfite, 400 ml of water and 84 grams (1.0 moles) of anhydrous sodium bicarbonate in sequence in the reaction flask; start stirring, heat to...

Embodiment 1

[0067] This embodiment is used to illustrate the preparation of 2-nitro-4-thiamphenicol benzoic acid

[0068] Put 20.0g of 2-nitro-4-thiamphenicol chlorobenzene, 250ml of methanol and 34.1g of triethylamine into a 1L stainless steel autoclave, add 0.9g of palladium acetate and 2.1g of DPPP, fill with CO gas for replacement three times, and pass into CO to 2MPa, heat up to 170°C, heat and hold pressure for 2 hours, cool down, filter, filtrate is precipitated under negative pressure, add 500ml of water and add 30% by weight hydrochloric acid to adjust the pH to 2, heat up to 50°C, heat for 1 hour, cool down to 20 ℃, filter, wash the filter cake with 25ml of water, dry the filter cake at 90 ℃, get 17.8g product (identified as 2-nitro-4-thiamphenicol benzoic acid through NMR and mass spectrometry), yield 85.2% , a purity of 98.5% by weight.

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Abstract

The invention relates to the field of herbicides, and discloses a preparation method of 2-nitro-4-methylsulfonylbenzoic acid. The preparation method of 2-nitro-4-methylsulfonylbenzoic acid comprises the following steps of: (1) in the presence of alkali and in the presence of a catalyst and a catalyst ligand, carrying out coupling reaction on 2-nitro-4-methylsulfonylchlorobenzene, carbon monoxide and alcohol with the carbon atom number of 1-3 to obtain 2-nitro-4-methylsulfonylbenzoic acid alkyl ester; and (2) carrying out a hydrolysis reaction on the 2-nitro-4-methylsulfonylbenzoic acid alkyl ester obtained in the step (1), the catalyst being one or more of palladium acetate, palladium chloride, palladium nitrate and cupric acetate, and the catalyst ligand being one or more of triphenylphosphine, bis (diphenylphosphino) ethane, bis (diphenylphosphino) propane, bis (diphenylphosphino) benzene and bis (diphenylphosphino) dimethyl xanthene. The preparation method is simple and convenient to operate, and is safe and environment-friendly because nitric acid and sulfuric acid mixed acid is not used as an oxidizing agent, a heavy metal oxidizing agent, toxic raw materials and the like.

Description

technical field [0001] The invention relates to the field of herbicides, in particular to a preparation method of 2-nitro-4-thiamphenicol benzoic acid. Background technique [0002] Mesotrione (Mesotrione), also known as mesotrione, mesotrione, chemical name is 2-(2-nitro-4-thiamphenicol benzoyl) cyclohexane-1,3-dione, A triketone herbicide developed by Syngenta. As a new type of systemic herbicide dedicated to corn fields, mesotrione has the characteristics of broad herbicidal spectrum, high activity, strong miscibility, safety to crops, and strong environmental compatibility. It has great prospects for development and use in my country. [0003] 2-nitro-4-thiamphenicol benzoic acid (NMSBA) is an important intermediate in the synthesis of mesotrione, with a molecular weight of 245.21 and a melting point of 211-212°C. It is a white or light yellow solid at room temperature. It can be prepared by oxidation of 2-nitro-4-thiamphenicol toluene (NMST): [0004] [0005] The...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C317/44C07C315/04
CPCC07C315/04C07C2531/24C07C317/44
Inventor 汪韬王磊吴坤倪肖元曹璐郭晓伟李辛夷乔振
Owner NUTRICHEM LAB CO LTD
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