Synthetic method of substituted indol-2-formic acid

A synthesis method and indole technology, which is applied in the synthesis of important intermediates of medicine and pesticides, and in the field of synthesis of substituted indole-2-carboxylic acid, can solve the problem of waste gas, waste water, waste, unfavorable industrial application, complex process, etc. problems, to achieve the effects of environmental friendliness, significant social and economic benefits, and easy availability of raw materials

Inactive Publication Date: 2015-03-11
CHINA AGRI UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] Generally speaking, the current synthesis method has complex process, relatively high cost, and a lot of waste gas, waste water, and waste, which is not conducive to industrial application

Method used

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  • Synthetic method of substituted indol-2-formic acid

Examples

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example 1

[0035] Example 1. Synthesis of indole-2-carboxylic acid

[0036] Using ethanol as the solvent, heat 108 g of phenylhydrazine, 1 ml of acetic acid and 127 g of ethyl pyruvate in a mixed solvent of 1175 ml of ethanol and 235 ml of water, and reflux at a temperature of 80°C. Monitor the completion of the reaction for 3 hours. After the solvent, it was recrystallized with a 70% ethanol aqueous solution, filtered, and dried to obtain 177 g of light yellow crystal phenylhydrazine pyruvic acid phenylhydrazone with a yield of 86%.

[0037] Step 2: Mix 500 grams of polyphosphoric acid and 250 grams of phosphoric acid, and add 75 grams of raw material phenylhydrazine pyruvic acid phenylhydrazone in batches while heating to 50°C under stirring, and control the temperature in the range of 70~90°C for 0.5 hours After adding the raw materials, continue the temperature control reaction for 20 minutes, monitor the completion of the reaction, pour it into 1500 grams of ice-water mixture, cool, filt...

example 2

[0040] Example 2. Synthesis of 5-fluoroindole-2-carboxylic acid

[0041] Step 1: Using ethanol as the solvent, heat 162.5 g of 4-fluorophenylhydrazine hydrochloride and 127 g of ethyl pyruvate in a mixed solvent of 1205 ml of ethanol and 241 ml of water, and reflux at 80°C for 4 hours After monitoring the completion of the reaction and removing the solvent, it was recrystallized with a 70% ethanol aqueous solution, filtered, and dried to obtain 186.1 g of pale yellow crystals of 4-fluorophenylhydrazine pyruvate phenylhydrazone with a yield of 83%.

[0042] Step 2: Mix 500 g of polyphosphoric acid and 250 g of phosphoric acid, and under the condition of heating to 75°C under stirring, add 65 g of 4-fluorophenylhydrazine pyruvic acid phenylhydrazone in batches, and control the temperature in the range of 75~85°C After adding the raw materials in 1 hour, continue the temperature control reaction for 20 minutes, monitor the completion of the reaction, pour it into 1500 grams of ice-wat...

example 3、5

[0045] Example 3. Synthesis of 5-chloroindole-2-carboxylic acid

[0046] Using ethanol as the solvent, heat 179.05 g 4-chlorophenylhydrazine hydrochloride and 127 g ethyl pyruvate in a mixed solvent of 1225 ml methanol and 265 ml water, reflux at a temperature of about 80°C, and monitor the reaction for 3 hours After the solvent was removed, it was recrystallized with 70% ethanol aqueous solution, filtered, and dried to obtain 219 grams of 4-chlorophenylhydrazine pyruvic acid phenylhydrazone with a yield of 91%.

[0047] Step 2: Mix 500 grams of polyphosphoric acid and 250 grams of phosphoric acid, heat to 70°C under stirring, add 70 grams of 4-chlorophenylhydrazine pyruvate phenylhydrazone in batches, and control the temperature in the range of 70~90°C for 1 hour After adding the raw materials, continue the temperature control reaction for 40 minutes, monitor the completion of the reaction, pour it into 1500 grams of ice-water mixture, cool, filter and dry to obtain a pale yellow ...

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Abstract

The invention discloses a synthetic method of substituted indol-2-formic acid. Substituted phenylhydrazine hydrochloride or phenylhydrazine is used as a raw material, hydrazone is formed through ethyl pyruvate, then substituted indol-2-ethyl formate is obtained through a Fischer indol synthetic reaction, and the substituted indol-2-formic acid is obtained after hydrolysis. The product purity is greater than 97%, and the reaction yield is 64%. The synthetic method disclosed by the invention has the characteristics of being free of severe conditions, simple to operate and environment-friendly, and has certain economic benefit. According to the synthetic method of the indol-2-formic acid, the raw materials are easily obtained, the operation is simple and convenient, three wastes are few, and the yield is high.

Description

Technical field [0001] The invention relates to the synthesis of an important intermediate for medicines and pesticides, especially a synthesis method of substituted indole-2-carboxylic acid. It belongs to the field of organic synthesis. Background technique [0002] Instead of indole-2-carboxylic acid medicine, an important intermediate of pesticides, with the in-depth development of pyrimidine pesticides and medicines, indole-2-carboxylic acid has been more and more widely used as an intermediate. Therefore, the research and development of substituted indole-2-carboxylic acid is of great significance. [0003] At present, there are mainly the following methods for the synthesis of substituted indole-2-carboxylic acid: [0004] One: Hemetersberger reaction, by condensing substituted benzaldehyde with ethyl azide ethyl acetate, and then closing the ring under catalytic heating conditions to obtain substituted indole-2-carboxylate, and then hydrolyzing to obtain acid. This method ha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D209/42
CPCC07D209/42
Inventor 黄家兴解晓平
Owner CHINA AGRI UNIV
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