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Preparation method of 2-amino-6-nitrobenzoic acid

A technology of nitrobenzoic acid and amino, which is applied in the preparation of organic compounds, cyanide reaction preparation, chemical instruments and methods, etc. It can solve the problems of difficult synthesis of ammonolysis process, difficult preparation of raw materials, difficult acquisition, etc., and achieve product purity Good, simple post-processing operation, and reduced side effects

Active Publication Date: 2013-02-13
LIANHE CHEM TECH +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0016] The technical problem to be solved by the present invention is to overcome the defects such as difficulty in raw material preparation, high price and difficulty in obtaining in the preparation method of existing 2-amino-6-nitrobenzoic acid, and difficult synthesis of traditional ammonolysis process, etc., and provide A method for preparing 2-amino-6-nitrobenzoic acid by ammonolysis with cheap and easy-to-obtain 2-halogeno-6-nitrobenzoic acid as starting raw material and cuprous compound as catalyst; the preparation The method is low in cost, simple in process, less in side reactions, simple in post-treatment operation, and suitable for large-scale industrial production

Method used

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  • Preparation method of 2-amino-6-nitrobenzoic acid
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  • Preparation method of 2-amino-6-nitrobenzoic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0043]Put 20.3g of 2-chloro-6-nitrobenzoic acid, 1.2g of cuprous oxide, 40g of cesium carbonate, 50g of DMF and 85g of 30% self-mixed ammonia into a 500mL autoclave. Raise the temperature to 90°C, pass ammonia gas during the reaction to maintain the pressure in the kettle at 0.7-0.8 MPa, and react for 12 hours. Sampling control. The phases were separated and the upper layer was collected. Add hydrochloric acid to acidify to pH 1-2. Filter and collect the filtrate. Add diethyl ether to extract three times, and collect the upper diethyl ether phase. Distillation and desolvation gave 18.7 g of A-NBA crude product (HPLC content of A-NBA: 88%), converted yield: 90%. Recrystallization was carried out with ethyl acetate to obtain 15.5 g of A-NBA product (HPLC purity>97%), the total yield: 85%. 1 HNMR (DMSO-d 6 ,400MHz): δ6.9(1H,d,J=8Hz), δ7.0(1H,d,J=8Hz), δ7.3(1H,t,J=8Hz), δ8.7(2H,s ). ESI-MS m / z: 181.0221[M-H] - .

Embodiment 2

[0045] Put 29.6g of 2-iodo-6-nitrobenzoic acid, 1.9g of cuprous iodide, 100g of ethanol and 68g of 30% self-made ammonia into a 500mL autoclave. The temperature was raised to 100°C, and the reaction was carried out for 15 hours. During the reaction, the system pressure dropped from 1.1 MPa to 0.8 MPa. Sampling control. Add hydrochloric acid to acidify to pH 2-3. Add ethyl acetate to extract three times, and collect the ethyl acetate phase. Under reduced pressure, 18.8 g of crude A-NBA was obtained (HPLC content of A-NBA: 89%), and the converted yield was 92%. Recrystallization was carried out with ethyl acetate / petroleum ether mixed solvent to obtain 15.8 g of A-NBA product (HPLC purity > 97%), and the total yield: 87%. 1 HNMR (DMSO-d 6 ,400MHz): δ6.9(1H,d,J=8Hz), δ7.0(1H,d,J=8Hz), δ7.3(1H,t,J=8Hz), δ8.7(2H,s ). ESI-MS m / z: 181.0221[M-H] - .

Embodiment 3

[0047] Put 24.8g of 2-bromo-6-nitrobenzoic acid, 1.2g of cuprous bromide, 100g of isopropanol and 68g of 30% self-made ammonia into a 500mL autoclave. The temperature was raised to 105°C, and the reaction was carried out for 15 hours. During the reaction, the system pressure dropped from 1.2MPa to 0.9MPa. Sampling control. Add sulfuric acid to acidify to pH 1-2. Add ethyl acetate to extract three times, and collect the ethyl acetate phase. Under reduced pressure, 18.4 g of crude A-NBA was obtained (HPLC content of A-NBA: 90%), and the converted yield was 91%. Recrystallization was carried out with ethyl acetate / hexane mixed solvent to obtain 15.7 g of A-NBA product (HPLC purity > 97%), and the total yield: 86%. 1 HNMR (DMSO-d 6 ,400MHz): δ6.9(1H,d,J=8Hz), δ7.0(1H,d,J=8Hz), δ7.3(1H,t,J=8Hz), δ8.7(2H,s ). ESI-MS m / z: 181.0221[M-H] - .

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Abstract

The invention discloses a preparation method of 2-amino-6-nitrobenzoic acid, which comprises the following steps: reacting 2-halo-6-nitrobenzoic acid with ammonia according to a formula shown in the specification in an organic solvent under the function of a cuprous catalyst, wherein X is F, Cl, Br or I. According to the preparation method, the cheap and available 2-halo-6-nitrobenzoic acid is used as a raw material to greatly reduce the production cost; the cuprous catalyst is used for catalyzing the aminolysis, the reaction condition is mild, and the requirement and consumption on equipment is reduced; the reaction conversion rate is high, the side reaction is decreased, the after-treatment operation is simple, the yield is high, the product purity is good, and the method is suitable for industrial production.

Description

technical field [0001] The present invention specifically relates to a kind of preparation method of 2-amino-6-nitrobenzoic acid. Background technique [0002] 2-Amino-6-nitrobenzoic acid is an important pesticide, pharmaceutical and fine chemical intermediate. [0003] Currently reported 2-amino-6-nitrobenzoic acid synthesis methods mainly contain three kinds: 2,6-dinitrobenzoic acid method, 2-carbamoyl-6-nitrobenzoic acid method and 3-nitro-o- Phthalimide method. [0004] In the patent US20100094046, a method for synthesizing 2-amino-6-nitrobenzoic acid by reducing 2,6-dinitrobenzoic acid with sodium bisulfide in a water-methanol system was reported, using sodium bicarbonate as a buffer. The method has a high yield (93%), but the raw material 2,6-dinitrobenzoic acid used in the synthesis method is difficult to prepare, expensive and not easy to obtain. The reaction equation is as follows: [0005] [0006] Patent US20110301178 reports a method for synthesizing 2-ami...

Claims

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Application Information

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IPC IPC(8): C07C229/56C07C227/08
Inventor 王萍樊小彬李利奎章周舜
Owner LIANHE CHEM TECH
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