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Method for preparing N-methyl isatoic anhydride

A technology of methyl isatoic anhydride and methyl anthranilic acid is applied in the field of preparation of N-methyl isatoic anhydride, and can solve the problems of low yield, difficult availability of raw material N-methyl anthranilic acid and the like , to achieve the effect of short reaction time, cheap and easy-to-obtain raw materials, and high yield

Active Publication Date: 2013-12-18
SHAANXI JIAHE PHYTOCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] Patent CN201010265405 reports that the raw material N-methyl anthranilic acid is refluxed under ethyl chloroformate to close the ring, and N-methyl isatoic anhydride is obtained with a yield of 70%. However, the raw material N-methyl anthranilic acid It is not easy to get in the market, and ethyl chloroformate is also a highly toxic product, and the yield is not high

Method used

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  • Method for preparing N-methyl isatoic anhydride

Examples

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Effect test

Embodiment 1

[0028] 1, the preparation of N-methyl anthranilic acid

[0029] Feed 62.4g of o-chlorobenzoic acid, 105g of methylamine solution, 28g of anhydrous potassium carbonate, 3g of copper powder, and 40ml of DMF, stir evenly, heat up to 110°C, react for 1h, and stop the reaction. Cool to room temperature, add 100ml of 1:1 glacial acetic acid aqueous solution, and let stand for 2h. Filter and wash with water to obtain 58 g of white solid, which is N-methylanthranilic acid. The yield was 87.8%.

[0030] 2. Preparation of N-methylisatoic anhydride

[0031] Feed 15g of N-methylanthranilic acid and 60ml of dichloromethane, cool down at 0-5°C, slowly add 14g of triphosgene, raise the temperature to 20°C, and react for 2h. Stop the reaction, add 100ml of water, separate the organic phase, wash with water until neutral, recover the solvent under reduced pressure to obtain a white solid, and refine it with ethanol to obtain 15.4g of fine product. The yield was 96%.

Embodiment 2

[0033] 1, the preparation of N-methyl anthranilic acid

[0034] Feed 62.4g of o-chlorobenzoic acid, 145g of methylamine solution, 36.4g of anhydrous potassium carbonate, 3.2g of copper powder, and 50ml of water, stir well, heat up to 80°C, react for 45min, and stop the reaction. Cool to room temperature, add 120ml of 1:1 glacial acetic acid aqueous solution, and let stand for 3h. Filter and wash with water to obtain 52 g of white solid, which is N-methylanthranilic acid. The yield was 78.9%.

[0035] 2. Preparation of N-methylisatoic anhydride

[0036] Feed 15g of N-methylanthranilic acid and 60ml of dichloromethane, cool down at 0-5°C, slowly add 12.5g of triphosgene, warm up to room temperature, and react for 2h. Stop the reaction, add 100ml of water, separate the organic phase, wash with water until neutral, recover the solvent under reduced pressure to obtain a white solid, and refine it with ethanol to obtain 15.5g of fine product. The yield was 97%.

Embodiment 3

[0038] 1, the preparation of N-methyl anthranilic acid

[0039] Feed 62.4g of o-chlorobenzoic acid, 108g of methylamine solution, 30.84g of anhydrous potassium carbonate, 3g of copper powder, and 50ml of water, stir well, heat up to 80°C, react for 30min, and stop the reaction. Cool to room temperature, add 120ml of 1:1 glacial acetic acid aqueous solution, and let stand for 2h. Filter and wash with water to obtain 49 g of white solid. The yield was 74%.

[0040] 2. Preparation of N-methylisatoic anhydride

[0041] Feed 15g of N-methylanthranilic acid and 60ml of toluene, cool down at 0-5°C, slowly add 17.5g of triphosgene, raise the temperature to room temperature at°C, and react for 3.5h. Stop the reaction, add 100ml of water, separate the organic phase, wash with water until neutral, recover the solvent under reduced pressure to obtain a white solid, and refine it with ethanol to obtain the fine product 15.2. The yield is 95%.

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Abstract

The invention provides a method for preparing N-methyl isatoic anhydride. The method comprises simple steps, is simple and convenient to operate, and is suitable for industrial production, and the raw materials are cheap and are easily available. The method comprises following steps of firstly taking anhydrous potassium carbonate as acid-binding agent and copper powder as a catalyst, carrying out a condensation reaction on o-chlorobenzoic acid and methylamine so as to obtain N-methyl o-aminobenzoic acid, and carrying out cyclization through condensation by adopting triphosgene and N-methyl o-aminobenzoic acid, so as to prepare the N-methyl isatoic anhydride.

Description

technical field [0001] The invention belongs to the field of organic chemistry and relates to a preparation method of N-methyl isatoic anhydride. Background technique [0002] N-Methylisatoic anhydride, English name N-Methylisatoic anhydride, chemical name, 1-methyl-2H-3,1-benzoxazine 2,4(1H)-dione, molecular formula: C9H7NO3CAS: 10328-92 -4. [0003] [0004] N-methylisatoic anhydride, used as raw material for medicine, pesticide and dyestuff, is an important intermediate of herbicide bendazone, and also an intermediate of emergency life-saving new drug Laquinimod tablets (Laquinimod), as well as a natural product The key intermediate of evodiamine. [0005] About the preparation method of N-methyl isatoic anhydride, there are not many domestic literature reports. [0006] The conventional preparation method is to carry out methylation reaction with isatoic anhydride under a methylating agent such as methyl iodide or dimethyl sulfate. In 2012, Dong Guoqiang, Darras, ...

Claims

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Application Information

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IPC IPC(8): C07D265/26
Inventor 肖金霞郭文华王春德
Owner SHAANXI JIAHE PHYTOCHEM
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