The synthetic method of substituted indole-2-carboxylic 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 environmental friendliness, significant social and economic benefits, and easy access to raw materials

Inactive Publication Date: 2017-10-13
CHINA AGRI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

First of all, organic solvents must be used, because polyphosphoric acid is very viscous, and it is difficult to stir even under heating conditions; there are many by-products in the reaction, and the post-processing is troublesome. and other steps
Although some substrates react well, most substrates are poor
[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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  • The synthetic method of substituted indole-2-carboxylic acid
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  • The synthetic method of substituted indole-2-carboxylic acid

Examples

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Effect test

example 1

[0035] Example 1, the synthesis of indole-2-carboxylic acid

[0036] Using ethanol as a solvent, heat 108 grams of phenylhydrazine, 1 milliliter of acetic acid and 127 grams of ethyl pyruvate in a mixed solvent of 1175 milliliters of ethanol and 235 milliliters of water, reflux at a temperature of 80 ° C, and monitor the completion of the reaction in 3 hours. After solvent, recrystallize with 70% ethanol aqueous solution, filter, and dry to obtain 177 g of light yellow crystal phenylhydrazinepyruvate phenylhydrazone, with a yield of 86%.

[0037] Step 2: Mix 500 grams of polyphosphoric acid and 250 grams of phosphoric acid, stir and heat to 50°C, add 75 grams of raw material phenylhydrazinepyruvate phenylhydrazone in batches, and control the temperature range from 70 to 90°C for 0.5 hours After adding the raw materials, continue the temperature control reaction for 20 minutes, monitor that the reaction is complete, pour it into 1500 grams of ice-water mixture, cool, filter and...

example 2

[0040] The synthesis of example 2,5-fluoroindole-2-formic acid

[0041] Step 1: Using ethanol as a solvent, heat 162.5 grams of 4-fluorophenylhydrazine hydrochloride and 127 grams of ethyl pyruvate in a mixed solvent of 1205 milliliters of ethanol and 241 milliliters of water, and reflux at a temperature of 80 ° C for 4 hours After monitoring the completion of the reaction, after removing the solvent, recrystallize with 70% ethanol aqueous solution, filter, and dry to obtain 186.1 g of light yellow crystal 4-fluorophenylhydrazinepyruvate phenylhydrazone, with a yield of 83%.

[0042] Step 2: Mix 500 grams of polyphosphoric acid and 250 grams of phosphoric acid, stir and heat to 75°C, add 65 grams of raw material 4-fluorophenylhydrazinepyruvate phenylhydrazone in batches, and control the temperature range from 75 to 85°C , add 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...

example 3、5

[0045] The synthesis of example 3,5-chloroindole-2-formic acid

[0046] Using ethanol as a solvent, heat 179.05 grams of 4-chlorophenylhydrazine hydrochloride and 127 grams of ethyl pyruvate in a mixed solvent of 1225 milliliters of methanol and 265 milliliters of water, reflux at a temperature of about 80 ° C, and monitor the reaction for 3 hours Completed, after desolvation, recrystallized with 70% ethanol aqueous solution, filtered, and dried to obtain 219 grams of light yellow crystal 4-chlorophenylhydrazinepyruvate phenylhydrazone, yield 91%.

[0047] Step 2: Mix 500 grams of polyphosphoric acid and 250 grams of phosphoric acid, heat it to 70°C under stirring, add 70 grams of raw material 4-chlorophenylhydrazinepyruvate phenylhydrazone in batches, control the temperature range from 70 to 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 mixt...

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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 of medicine and pesticide, especially the synthesis method of substituted indole-2-carboxylic acid. It belongs to the field of organic synthesis. Background technique [0002] Substituting 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 acids is of great significance. [0003] At present, there are several methods for the synthesis of substituted indole-2-carboxylic acids: [0004] One: Hemetersberger reaction, condensation of substituted benzaldehyde and ethyl azidoacetate, and then ring-closing under catalytic heating conditions to obtain substituted indole-2-carboxylate, and then hydrolyzed to obtain acid. This type of method has a ...

Claims

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Application Information

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