Industrial preparation method for 3-amino phenylacetic acid

Abstract

The invention relates to a process for preparing 3-amino phenylacetic acid with p-nitro benzyl cyanide as raw materials, by reduction, acetylation, nitrification, hydrolysis, esterification, deamination, reduction and hydrolysis. The invention has high selectivity and the raw materials are cheap and easily available.

Description

technical field

[0001] The invention relates to a preparation method of 3-aminophenylacetic acid. Background technique

[0002] 3-Aminophenylacetic acid is an important chemical intermediate, which can be used in the synthesis of antibacterial agents, insecticides and hair dyes. The preparation method of multiple 3-aminophenylacetic acid has been reported in the existing literature, summarized as follows:

[0003] (1) J.Amer.Chem.Soc.; 82; 1960; 1975, 1981 reported that m-nitrobenzaldehyde was used as raw material to be reduced to benzyl alcohol by hydrogenation, and then finally brominated, cyanided, reduced and hydrolyzed. Obtain target product m-aminophenylacetic acid:

[0004]

[0005] In this reaction route, not only high-pressure reaction is required, but also highly toxic drug cuprous cyanide is used. Simultaneously each step reaction yield is lower, as accomplishing benzyl bromide from m-nitrobenzaldehyde only has 40% yield, and accomplishes final product from ...

Examples

Embodiment

[0028] Add 200ml of water into the three-necked flask, add 80g of iron powder under mechanical stirring, reflux with 4ml of acetic acid for 30min, cool down to 90-95°C, add 64.8g of p-nitrophenylacetonitrile in batches, reflux for 4hr after the addition, and cool down to 80°C , add 200ml of dichloroethane, filter with suction, wash the filter cake with hot dichloroethane, separate the organic layer, and precipitate under reduced pressure to obtain 50.1 g of the product p-aminophenylacetonitrile, with a yield of 95%.

[0029] Add 24.5ml acetic acid to 52.8g p-aminophenylacetonitrile, add dropwise 24.5ml acetic anhydride at room temperature, continue to react for 1hr after dripping, the reaction solution is poured into ice water, and suction filtration obtains 63.3g of product p-acetamidophenylacetonitrile, the yield 91%.

[0030] Add 91ml of 60% nitric acid dropwise to 91ml of concentrated sulfuric acid, add 34.8g of p-acetaminophenylacetonitrile in batches under ice water cool...

technical field

[0001] The invention relates to a preparation method of 3-aminophenylacetic acid. Background technique

[0002] 3-Aminophenylacetic acid is an important chemical intermediate, which can be used in the synthesis of antibacterial agents, insecticides and hair dyes. The preparation method of multiple 3-aminophenylacetic acid has been reported in the existing literature, summarized as follows:

[0003] (1) J.Amer.Chem.Soc.; 82; 1960; 1975, 1981 reported that m-nitrobenzaldehyde was used as raw material to be reduced to benzyl alcohol by hydrogenation, and then finally brominated, cyanided, reduced and hydrolyzed. Obtain target product m-aminophenylacetic acid:

[0004]

[0005] In this reaction route, not only high-pressure reaction is required, but also highly toxic drug cuprous cyanide is used. Simultaneously each step reaction yield is lower, as accomplishing benzyl bromide from m-nitrobenzaldehyde only has 40% yield, and accomplishes final product from ...

Examples

Embodiment

[0028] Add 200ml of water into the three-necked flask, add 80g of iron powder under mechanical stirring, reflux with 4ml of acetic acid for 30min, cool down to 90-95°C, add 64.8g of p-nitrophenylacetonitrile in batches, reflux for 4hr after the addition, and cool down to 80°C , add 200ml of dichloroethane, filter with suction, wash the filter cake with hot dichloroethane, separate the organic layer, and precipitate under reduced pressure to obtain 50.1 g of the product p-aminophenylacetonitrile, with a yield of 95%.

[0029] Add 24.5ml acetic acid to 52.8g p-aminophenylacetonitrile, add dropwise 24.5ml acetic anhydride at room temperature, continue to react for 1hr after dripping, the reaction solution is poured into ice water, and suction filtration obtains 63.3g of product p-acetamidophenylacetonitrile, the yield 91%.

[0030] Add 91ml of 60% nitric acid dropwise to 91ml of concentrated sulfuric acid, add 34.8g of p-acetaminophenylacetonitrile in batches under ice water cool...

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