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Pharmaceutical intermediate 3,4-dimethoxy-6-nitrobenzoic acid synthesis method

A technology of nitrobenzoic acid and dimethoxy, which is applied in chemical instruments and methods, preparation of organic compounds, preparation of carboxylate, etc., can solve problems such as complex process and low final yield, and reduce intermediate links , shorten the reaction time, improve the effect of reaction yield

Inactive Publication Date: 2018-07-03
CHENGDU DONG DIAN AI ER TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] 3,4-dimethoxy-6-nitrobenzoic acid is used as a pharmaceutical intermediate, mainly used in the synthesis of drugs such as prazosin, but most of the existing synthetic methods use reedral as a reactant, and the process is more complicated. The final yield is not very high, therefore, it is necessary to propose a new synthetic method, which has important economic significance for further improving the quality and yield of the product and reducing the content of by-products

Method used

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  • Pharmaceutical intermediate 3,4-dimethoxy-6-nitrobenzoic acid synthesis method

Examples

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Effect test

example 1

[0010] Add 3mol of 2-bromo-3,4-dimethoxy-6-aminoacetophenone and 6mol of 1,5-pentanediol solution into the reaction vessel, control the stirring speed at 210rpm, keep it for 30min, add 600ml mass fraction 10% potassium carbonate solution, adjust the pH to 8, increase the solution temperature to 60°C, add 3mol of nickel oxide, continue the reaction for 30min, add a 20% potassium hydrogensulfate solution by mass fraction, adjust the pH to 2, Reduce the solution temperature to 10°C, wash with 30% sodium sulfate solution in mass fraction, wash with 75% methylcyclohexanone solution, wash with 80% 1-methylnaphthalene solution with 90% mass fraction % of 2-methyl-3-pentanol solution and dehydrated with anhydrous potassium carbonate dehydrating agent to obtain 606.09 g of finished product 3,4-dimethoxy-6-nitrobenzoic acid with a yield of 89%.

example 2

[0012] Add 3mol of 2-bromo-3,4-dimethoxy-6-aminoacetophenone and 7mol of 1,5-pentanediol solution into the reaction vessel, control the stirring speed at 230rpm, keep it for 35min, add 600ml mass fraction For 13% potassium carbonate solution, adjust the pH to 8.5, increase the temperature of the solution to 65°C, add 4mol of nickel oxide, continue the reaction for 35min, add a 23% potassium hydrogensulfate solution by mass fraction, adjust the pH to 2.5, Lower the solution temperature to 12°C, wash with 32% sodium sulfate solution in mass fraction, wash with methylcyclohexanone solution with 79% mass fraction, wash with 1-methylnaphthalene solution with 83% mass fraction, and wash with 93% mass fraction % of 2-methyl-3-pentanol solution and dehydrated with anhydrous magnesium sulfate dehydrating agent to obtain 626.52 g of finished product 3,4-dimethoxy-6-nitrobenzoic acid with a yield of 92%.

example 3

[0014] Add 3mol of 2-bromo-3,4-dimethoxy-6-aminoacetophenone and 8mol of 1,5-pentanediol solution into the reaction vessel, control the stirring speed at 250rpm, keep it for 40min, add 600ml mass fraction For a 17% potassium carbonate solution, adjust the pH to 9, increase the temperature of the solution to 70°C, add 5mol of nickel oxide, continue the reaction for 40min, add a 26% potassium bisulfate solution by mass fraction, adjust the pH to 3, Lower the solution temperature to 15°C, wash with 35% sodium sulfate solution in mass fraction, wash with 82% methylcyclohexanone solution, wash with 86% 1-methylnaphthalene solution, and wash with 97% mass fraction % of 2-methyl-3-pentanol solution and dehydrated with anhydrous calcium sulfate dehydrating agent to obtain 653.76 g of finished product 3,4-dimethoxy-6-nitrobenzoic acid with a yield of 96%.

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Abstract

The invention relates to a pharmaceutical intermediate 3,4-dimethoxy-6-nitrobenzoic acid synthesis method, which mainly comprises: adding 3 mol 2-bromo-3,4-dimethoxy-6-aminoacetophenone and 6-8 mol 1,5-pentanediol solution into a reaction container, controlling the stirring speed at 210-250 rpm, maintaining for 30-40 min, adding 600 ml of a potassium carbonate solution, adjusting the pH value to 8-9, increasing the solution temperature to 60-70 DEG C, adding 3-5 mol nickel oxide, continuously carrying out the reaction for 30-40 min, adding a potassium hydrogen sulfate solution, adjusting the pH value to 2-3, reducing the solution temperature to 10-15 DEG C, washing with a sodium sulfate solution, washing with a methylcyclohexanone solution, washing with a 1-methylnaphthalene solution, re-crystallizing in a 2-methyl-3-pentanol solution, and dehydrating with a dehydrating agent to obtain the finished product 3,4-dimethoxy-6-nitrobenzoic acid.

Description

technical field [0001] The invention relates to a method for synthesizing a pharmaceutical intermediate 3,4-dimethoxy-6-nitrobenzoic acid. Background technique [0002] 3,4-dimethoxy-6-nitrobenzoic acid is used as a pharmaceutical intermediate, mainly used for the synthesis of drugs such as prazosin, but most of the existing synthetic methods use reedral as a reactant, and the process is more complicated. The final yield is not very high. Therefore, it is necessary to propose a new synthetic method, which has important economic significance for further improving the quality and yield of the product and reducing the content of by-products. Contents of the invention [0003] The object of the present invention is to provide a kind of synthetic method of drug intermediate 3,4-dimethoxy-6-nitrobenzoic acid, comprising the steps: [0004] (i) Add 3mol of 2-bromo-3,4-dimethoxy-6-aminoacetophenone, 6-8mol of 1,5-pentanediol solution in the reaction vessel, control the stirring s...

Claims

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Application Information

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IPC IPC(8): C07C51/00C07C65/21
CPCC07C51/00C07C65/21
Inventor 严义达
Owner CHENGDU DONG DIAN AI ER TECH
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