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Method for preparing 2-amino-5-chloro-3-methylbenzoic acid

A technology of toluic acid and amino, which is applied in chemical instruments and methods, cyanide reaction preparation, organic compound preparation, etc., can solve the problems of high price and difficult post-processing, and achieve high overall yield, simple raw materials, The effect of easy access to raw materials

Inactive Publication Date: 2019-07-05
SUZHOU BLUEHILL BIOPHARMA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The chlorination reagent reported in existing literature and patents is N-chlorosuccinimide, which has the advantage that the reaction is very clean, but the price is very expensive, and it is only suitable for products with higher added value (CN103450154, CN104031026), and the reported reaction solvent It is DMF with a high boiling point, so it is difficult to carry out post-processing

Method used

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  • Method for preparing 2-amino-5-chloro-3-methylbenzoic acid
  • Method for preparing 2-amino-5-chloro-3-methylbenzoic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0012] At room temperature, in a 1000ml round bottom flask, add isatoic anhydride (60g, 396.92mmol), dichloroethane 180ml, at 25-30°C, slowly add cyanuric chloride (25.62g, 138.92mmol) in batches. After the addition, continue to stir for about 10 hours. The liquid phase detection of indigo raw materials is less than 1%, and the temperature is lowered to below 5°C. Suction filter, wash the solid twice with 50°C water (150ml), and dry it. Transfer to a reaction bottle, add anhydrous methanol (250ml), heat until the system dissolves, cool to below 5°C, filter with suction, and dry to obtain 62.6g of off-white solid with a yield of 85% and a liquid phase detection purity of 98.5 %.

[0013] 1H NMR (DMSO-d6) 7.55 (s, IH), 7.22 (s, IH), δ 2.11 (s, 3H).

Embodiment 2

[0015] At room temperature, add isatoic anhydride (5kg, 33.08mol) and 30L dichloroethane into a 50L reactor, and slowly add cyanuric chloride (2.13kg, 11.58mol) in batches at 25-30°C. After the addition, continue to stir for about 10 hours. The liquid phase detection of indigo raw materials is less than 1%, and the temperature is lowered to below 5°C. Suction filter, wash the solid twice with 50°C water (15L), and drain it. Transfer to a reaction bottle, add anhydrous methanol (20L), heat until the system dissolves, cool to below 5°C, filter with suction, and dry to obtain 5.1kg of off-white solid with a yield of 83% and a liquid phase detection purity of 98.8 %.

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Abstract

A method for preparing 2-amino-5-chloro-3-methylbenzoic acid is disclosed. The method includes steps of: adding 2-amino-3-methylbenzoic acid (compound-I) into a reaction solvent, with the reaction concentration being 5-10 times (the ratio of the solvent volume to the weight of the compound I) and the reaction temperature being 20-40 DEG C; adding cyanuric chloride (compound II) in batches; monitoring the reaction process through liquid chromatography; after the reaction is finished, performing filtration, washing with hot water and recrystallization with methanol to obtain 2-amino-5-chloro-3-methylbenzoic acid (compound III). According to the method, the 2-amino-3-methylbenzoic acid (compound-I) is adopted as an initial raw material and the cyanuric chloride (compound II) is adopted as a chlorination agent to prepare the compound III. The method has advantages of simple raw materials, simple after-treatment, and a high total yield, and can provide important references for industrial production.

Description

Technical field [0001] The present invention relates to a method for preparing 2-amino-5-chloro-3-methylbenzoic acid. Background technique [0002] 2-Amino-5-chloro-3-methylbenzoic acid is synthesized from 2-amino-3-methyl-5-chlorobenzamide insecticides (produced by Japanese pesticide companies, DuPont Company of the United States, Bayer Pesticide Technology, etc. The key intermediate of the new pesticide developed by the company, the trade name is "Kangkuan"). Due to the limitations of the existing process, the cost of synthesizing the intermediate 2-amino-3-methyl-5-chlorobenzamide is very high. The most limiting step is the synthesis of 2-amino-3-methylbenzoic acid from 2-amino-3-methylbenzoic acid. -5-Chloro-3-methylbenzoic acid. The chlorination reagent reported in existing literature and patents is N-chlorosuccinimide. The advantage is that the reaction is very clean, but the price is very expensive. It is only suitable for higher value-added products (CN103450154, C...

Claims

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Application Information

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IPC IPC(8): C07C227/16C07C229/56
CPCC07C227/16C07C229/56
Inventor 黄轩
Owner SUZHOU BLUEHILL BIOPHARMA CO LTD
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