Preparation method of 2,3,4-trimethoxybenzoic acid

A technology of trimethoxybenzoic acid and trimethoxybenzonitrile, which is applied in the field of pharmaceutical intermediates 2, can solve the problems of large pollution and high cost of raw materials, and achieve the effect of cheap raw materials and mild reaction conditions

Active Publication Date: 2013-05-08
JIANGSU POLYTECHNIC UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Making a general survey of domestic and foreign reports, there are mainly two synthetic routes about TBA: (1) is to be raw material with 2,3,4-trihydroxybenzoic acid, obtain through methylation with dimethyl sulfate, used in this method Dimethyl sulfate is a highly toxic chemical with high pollution
(2) is obtained through oxidation with 2,3,4-trimethoxybenzaldehyde, but there are also high raw material costs, a stoichiometric solid oxidant used in the oxidation process, and a large amount of slurry-like residue and waste produced in the production process. Acid, equipment corrosion is also quite serious and other problems

Method used

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  • Preparation method of 2,3,4-trimethoxybenzoic acid
  • Preparation method of 2,3,4-trimethoxybenzoic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0015] ①Weigh 31.5g of pyrogallic acid, 135g of dimethyl carbonate DMC and 54.76g of 1-n-butyl-3-methylimidazolium bromide, place them in a 500mL pressure-resistant reactor, stir them magnetically, and react at 150°C After 7 hours, cool to room temperature, then distill off low-boiling dimethyl carbonate DMC and methanol under reduced pressure, then extract with ether (150mL×3), combine the extracts, distill off part of the ether, and crystallize at low temperature Crude triphenylmethyl ether, dissolve the crude product in 150mL of petroleum ether, add 5g of activated carbon and heat it slightly (about 40°C, 30min), then heat filter, then wash the filter paper with 30mL of petroleum ether, evaporate part of the petroleum ether and put it in the refrigerator After crystallization, 38.9 g of pure white trityl ether was obtained, with a yield of 92.6%.

[0016] ②Add 35mL DMF and 16.8g (0.1mol) trityl ether into a 100mL four-neck flask, stir to dissolve completely, add 18.6g (0.10...

Embodiment 2

[0020] ① Weigh 31.5g of pyrogallic acid, 135g of DMC and 37.38g of 1-n-butyl-3-methylimidazolium bromide, place them in a 500mL pressure-resistant reactor and stir them magnetically, react at 150°C for 7h, finish, and cool to room temperature, then distill off low-boiling DMC and methanol under reduced pressure, then extract with diethyl ether (150mL×3), combine the extracts, distill off part of the diethyl ether, and crystallize at low temperature to obtain the crude trityl ether. Dissolve in 150mL of petroleum ether, add 5g of activated carbon, heat for a while (about 40°C, 30min), then heat filter, then wash the filter paper with petroleum ether, evaporate part of the petroleum ether and put it in the refrigerator to crystallize to obtain white trityl ether The pure product is 38.9g, and the yield is 92.6%.

[0021] ② Add 35ml DMF and 16.8g (0.1mol) trityl ether to a 100mL four-neck flask, stir to dissolve completely, add 18.6g (0.105mol) NBS in batches at no more than 20°C...

Embodiment 3

[0025] ① Weigh 31.5g of pyrogallic acid, 67.5g of DMC and 54.76g of 1-n-butyl-3-methylimidazolium bromide, place them in a 500mL pressure-resistant reactor and stir them magnetically, and react at 150°C for 7 hours. Cool to room temperature, distill off low-boiling DMC and methanol under reduced pressure, then extract with diethyl ether (150mL×3), combine the extracts, evaporate part of the diethyl ether, and then crystallize at low temperature to obtain the crude trityl ether. Dissolve in 150mL of petroleum ether, add 5g of activated carbon, heat for a while (about 40°C, 30min) and heat filter, then wash the filter paper with petroleum ether, evaporate part of the petroleum ether, put it in the refrigerator to crystallize to obtain pure white trityl ether The product was 38.9g, and the yield was 92.6%.

[0026]②Add 35mL DMF and 16.8g (0.1mol) trityl ether into a 100mL four-neck flask, stir to dissolve completely, add 18.6g (0.105mol) NBS in batches at no more than 20°C, and t...

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Abstract

The invention relates to a preparation method of 2,3,4-trimethoxybenzoic acid (TBA) shown as the following reaction equation. The method comprises the following steps of: methylating green chemical reagent dimethyl carbonate and coking gallic acid under the catalysis of ionic liquid, and then synthesizing the TBA through bromination, cyaniding and hydrolyzation, wherein the total yield of the TBA reaches 38.2%. The method has the advantages of low cost of raw materials and mild reaction condition and develops a route for synthesizing the TBA.

Description

technical field [0001] The invention relates to a method for synthesizing a pharmaceutical intermediate 2,3,4-trimethoxybenzoic acid (TBA). Background technique [0002] TBA is widely used as an important pharmaceutical intermediate, and its demand is increasing. Therefore, it is necessary to develop an effective synthetic route. [0003] Making a general survey of domestic and foreign reports, there are mainly two synthetic routes about TBA: (1) is to be raw material with 2,3,4-trihydroxybenzoic acid, obtain through methylation with dimethyl sulfate, used in this method Dimethyl sulfate is a highly toxic chemical with high pollution. (2) is obtained through oxidation with 2,3,4-trimethoxybenzaldehyde, but there are also high raw material costs, a stoichiometric solid oxidant used in the oxidation process, and a large amount of slurry-like residue and waste produced in the production process. Acid, corrosion of equipment is also quite serious and other problems. Contents...

Claims

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Application Information

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IPC IPC(8): C07C65/21C07C51/08
Inventor 陈兴权赵燕董燕敏赵万胜卿鹏程刘康
Owner JIANGSU POLYTECHNIC UNIVERSITY
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