Synthesis method of ethyl tetrazole-5-carboxylate

A technology of ethyl formate tetrazolium and ethyl formate tetrazolium sodium, which is applied in the field of synthesis of 5-ethyl tetrazolium formate, can solve the problems of long reaction time, unfavorable production, low reaction efficiency, etc. Achieve complete reaction, complete separation of impurities, and increase the effect of reaction rate

Active Publication Date: 2020-11-17
河北凯诺中星科技有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The solvent used in the reaction is DMF, which is a highly polar solvent. It is not conducive to recovery after the reaction, and DMF has genotoxicity
At the same time, this reaction takes a long time, and the reaction efficiency is low, which is not conducive to production.

Method used

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  • Synthesis method of ethyl tetrazole-5-carboxylate
  • Synthesis method of ethyl tetrazole-5-carboxylate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Add 40g (46.2mL) of toluene, 360g (360mL) of water, and 100g of ethyl cyanoformate into a 1L four-necked flask equipped with a stirring paddle, a condenser, and a thermometer, and start stirring. The mass ratio of ethyl cyanoformate to solvent (mixed solution of toluene and water) is 1:4, slowly add 65g of sodium azide to the reaction system several times, stir and raise the temperature to 90°C, and keep the reaction under reflux for 15h. Monitor the progress of the reaction. After the reaction is detected by TCL, water is added to the system while distilling out the toluene in the system under heat preservation until no toluene stratification remains in the remaining reflux liquid. In the actual operation process, toluene and water will be separated during the distillation process. It is observed that the fraction is not stratified. When the fraction is clarified, there will be no toluene left. As long as the toluene cannot be evaporated, it will be added continuously. ...

Embodiment 2

[0037] Add 40g (46.2mL) of toluene, 360g (360mL) of water, and 100g of ethyl cyanoformate into a 1L four-neck flask equipped with a stirring paddle, a condenser, and a thermometer, and start stirring. Slowly add 72.2 g of sodium azide to the reaction system multiple times, stir and raise the temperature to 90° C., and keep it under reflux for 16 hours. Monitor the reaction process, TCL detects that after the reaction is over, the toluene in the system is distilled out under the heat preservation state, and at the same time, water is replenished in the system in time until there is no toluene layer residue in the remaining reflux liquid. The amount of water added is not strictly limited. Preferably, the amount of water added each time is 30%-40% of the mass of toluene in the remaining reflux liquid. Cool down to 20°C, add 103 g of 36% HCl solution dropwise to the system, neutralize the pH to 3-4, and stir for 30 minutes. Cool down to 15°C, crystallize, and filter with suction....

Embodiment 3

[0039] Add 80g (92.4mL) of toluene, 320g (320mL) of water, and 100g of ethyl cyanoformate into a 1L four-necked flask equipped with a stirring paddle, a condenser, and a thermometer, and start stirring. Slowly add 65 g of sodium azide to the reaction system several times, stir and raise the temperature to 85° C., and keep the reaction under reflux for 14 hours. Monitor the reaction process, TCL detects that after the reaction is over, the toluene in the system is distilled out under the heat preservation state, and water is replenished in the system at the same time, until no toluene stratification remains in the remaining reflux liquid. Cool down to 30°C, add 103 g of 36% HCl solution dropwise to the system, neutralize to pH 3-4, and stir for 30 min. Cool down to 25°C to crystallize, filter with suction, the filter cake is the crude product of ethyl 5-formate tetrazolium, and the filter cake is recrystallized with a mixed solvent of 80% benzene / 20% water (m / m). The mass rati...

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Abstract

The invention relates to a method for synthesizing ethyl tetrazole-5-carboxylate, which belongs to the field of organic synthesis and comprises the following steps of: (1) heating and refluxing by taking ethyl cyanoformate and sodium azide as raw materials and a mixed solution of methylbenzene and water as a solvent to generate ethyl tetrazole-5-carboxylate sodium salt; (2) heating and distillingthe reflux liquid obtained in the step (1) to remove methylbenzene; (3) neutralizing the distillate obtained in the step (2) with an acidic solution, and conducting separating to obtain a crude product of ethyl tetrazole-5-carboxylate; and (4) recrystallizing the crude product of ethyl tetrazole-5-carboxylate through a mixed solvent of low-carbon hydrocarbon and water, and conducting separating toobtain ethyl tetrazole-5-carboxylate. The synthesis method disclosed by the invention is simple to operate and high in yield, and the purity of the prepared ethyl tetrazole-5-carboxylate is high.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular, the invention relates to a synthetic method of ethyl tetrazole 5-formate. Background technique [0002] As an important chemical and pharmaceutical intermediate, 5-ethyl tetrazolium formate is mainly used in laboratory research and chemical and pharmaceutical synthesis. Its most important use is to produce cysteinyl leukotriene (LTs) receptor antagonists Asthma drug Prenast is an anti-asthma drug with high efficiency, low toxicity and high safety, which has great medical research value and market prospect. [0003] At present about the synthetic report of 5-ethyl formate tetrazole, according to the difference of raw material and solvent, mainly be divided into following several, now summarize as follows: [0004] ①Ethyl cyanoformate and sodium azide are used as the basic raw materials, and DMF is used as the solvent. Researchers such as H. Yoneyama proposed to NaN 3 and Et 3 N·...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D257/04
CPCC07D257/04
Inventor 孙佳伟张琛李石磊杜照磊
Owner 河北凯诺中星科技有限公司
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