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Method for preparing 2-amino-3-alkyl-5-chlorobenzoic acid

A C2-C4, alkane technology, applied in chemical instruments and methods, cyanide reaction preparation, organic compound preparation, etc., can solve the problems of many reaction steps, many wastes, and cumbersome process

Pending Publication Date: 2021-07-13
LIER CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has high yield, but the preparation cost is too high due to the need to use expensive NCS
[0004] There are also other preparation methods reported, but these methods have many reaction steps, complicated process, low overall yield, and / or many problems such as three wastes

Method used

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  • Method for preparing 2-amino-3-alkyl-5-chlorobenzoic acid
  • Method for preparing 2-amino-3-alkyl-5-chlorobenzoic acid
  • Method for preparing 2-amino-3-alkyl-5-chlorobenzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Add 50 g of raw material 2-amino-3-methylbenzoic acid (0.331 mol) into the three-necked flask, then add 180 g of acetonitrile, cool down to -10°C and stir. Add 67 g of sulfuryl chloride (0.496 mol) and 50 g of acetonitrile into the constant pressure dropping funnel, slowly drop them into the reaction flask, and the dropping temperature is -10°C. After the dropwise addition, the temperature was maintained and stirring was continued for 10 h. The reaction liquid was detected by HPLC (215 nm), and the raw material accounted for 10.9%, and the product accounted for 85.6%.

Embodiment 2

[0044] Add 50 g of raw material 2-amino-3-methylbenzoic acid (0.331 mol) into the three-necked flask, then add 180 g of acetonitrile, cool down to 0° C. and stir. Add 67 g of sulfuryl chloride (0.496 mol) and 50 g of acetonitrile into the constant pressure dropping funnel, slowly drop them into the reaction flask, and the dropping temperature is 0°C. After the dropwise addition, the temperature was maintained and continued to stir for 2 h. The reaction liquid was detected by HPLC (215 nm), and the raw material accounted for 4.2%, and the product accounted for 92.3%.

Embodiment 3

[0046] Same as Example 2 except changing the reaction time to 10 h. HPLC detection (215nm) of the reaction solution showed that the raw material accounted for 4.0%, and the product was 90.3%.

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PUM

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Abstract

The invention relates to a method for preparing a compound as shown in a formula (I). The method comprises the following steps of: performing chlorination reaction on a raw material as shown in a formula (II) to obtain the compound as shown in the formula (I) by using sulfonyl chloride as a chlorination reagent and one or more solvents selected from dichloroC1-C4 alkane, C2-C4 nitrile, trichloroC1-C4 alkane, tetrachloroC1-C4 alkane and C2-C4 carboxylic acid, wherein R is C1-C4 alkyl; when the solvent is selected from C1-C4 alkane, trichloroC1-C4 alkane, tetrachloro C1-C4 alkane and C2-C4 carboxylic acid, the reaction temperature is in the range of 20-65 DEG C; and when the solvent is selected from C2-C4 nitriles, the reaction temperature is in the range of-10 DEG C to 10 DEG C.

Description

technical field [0001] The present invention relates to a process for the preparation of 2-amino-3-alkyl-5-chlorobenzoic acids. Background technique [0002] 2-Amino-3-alkyl-5-chlorobenzoic acid is an important pharmaceutical intermediate. In particular, 2-amino-3-methyl-5-chlorobenzoic acid is an important intermediate for the preparation of chlorantraniliprole (Kang Kuan). [0003] The preparation of 2-amino-3-methyl-5-chlorobenzoic acid is reported in the prior art, wherein, using 2-amino-3-methyl-benzoic acid as starting material, N-chlorosuccinyl Imine (NCS) is used as a chlorination reagent, N,N-dimethylformamide is used as a solvent, and the reaction is carried out at a temperature of 70-110°C. This method has high yield, but the preparation cost is too high due to the need to use expensive NCS. [0004] There are also other preparation methods reported, but these methods have problems such as many reaction steps, cumbersome process, low overall yield, and / or many ...

Claims

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Application Information

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IPC IPC(8): C07C227/16C07C229/56
CPCC07C227/16C07C229/56
Inventor 梁维平周磊何波李栋宏左翔程柯
Owner LIER CHEM CO LTD