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A kind of synthetic method of 2-ethyl-3,5,6-trimethylpyrazine

A technology of trimethylpyrazine and synthetic method, applied in the direction of organic chemistry, can solve the problems of low yield and purity, many side reactions, complicated operation, etc., and achieve the effect of high purity, short reaction time and simple operation

Active Publication Date: 2018-11-16
HEFEI PINGGUANG PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current method for synthesizing 2-ethyl-3,5,6-trimethylpyrazine has complex operations, many side reactions, and low yield and purity

Method used

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  • A kind of synthetic method of 2-ethyl-3,5,6-trimethylpyrazine
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  • A kind of synthetic method of 2-ethyl-3,5,6-trimethylpyrazine

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Embodiment 1

[0031] A kind of synthetic method of 2-ethyl-3,5,6-trimethylpyrazine, comprises the steps:

[0032] S1. Preparation of 1-oxo-2,3,5-trimethylpyrazine: After mixing 2,3,5-trimethylpyrazine and glacial acetic acid, add hydrogen peroxide aqueous solution, heat up, keep stirring, Concentrate under reduced pressure to remove glacial acetic acid, adjust pH=7, add dichloromethane for extraction, take the organic layer, concentrate under reduced pressure to remove dichloromethane to obtain 1-oxo-2,3,5-trimethylpyrazine, wherein, Aqueous hydrogen peroxide solution is divided into three additions, and each addition is identical;

[0033] S2. Preparation of 2-chloro-3,5,6-trimethylpyrazine: mix the 1-oxo-2,3,5-trimethylpyrazine obtained in S1 with phosphorus oxychloride, heat up, Insulate and stir to obtain solution A; add solution A to crushed ice, mix and cool down, adjust pH = 7, add dichloromethane for extraction, take the organic layer, concentrate under reduced pressure to remove d...

Embodiment 2

[0036] A kind of synthetic method of 2-ethyl-3,5,6-trimethylpyrazine, comprises the steps:

[0037] S1. Preparation of 1-oxo-2,3,5-trimethylpyrazine: After mixing 2,3,5-trimethylpyrazine and glacial acetic acid, add a 30 wt% hydrogen peroxide aqueous solution, Heat up to 80°C, keep stirring for 3 hours, concentrate under reduced pressure to remove glacial acetic acid, adjust pH=8 with saturated aqueous sodium carbonate solution, add dichloromethane for extraction, take the organic layer, dry, and concentrate under reduced pressure to remove dichloromethane to obtain 1-oxo -2,3,5-trimethylpyrazine, wherein, aqueous hydrogen peroxide solution is added in three times, the same amount added each time, the weight and volume of 2,3,5-trimethylpyrazine and aqueous hydrogen peroxide (g / ml) ratio is 5:47, 2,3,5-trimethylpyrazine, glacial acetic acid weight volume (g / ml) ratio is 1:9;

[0038] S2. Preparation of 2-chloro-3,5,6-trimethylpyrazine: mix the 1-oxo-2,3,5-trimethylpyrazine o...

Embodiment 3

[0041] A kind of synthetic method of 2-ethyl-3,5,6-trimethylpyrazine, comprises the steps:

[0042] S1. Preparation of 1-oxo-2,3,5-trimethylpyrazine: After mixing 2,3,5-trimethylpyrazine and glacial acetic acid, add 35 wt% aqueous hydrogen peroxide solution, Raise the temperature to 60°C, keep stirring for 5 hours, concentrate under reduced pressure to remove glacial acetic acid, adjust pH=6 with saturated aqueous sodium carbonate solution, add dichloromethane for extraction, take the organic layer, dry, and concentrate under reduced pressure to remove dichloromethane to obtain 1-oxo -2,3,5-trimethylpyrazine, wherein, aqueous hydrogen peroxide solution is added in three times, the same amount added each time, the weight and volume of 2,3,5-trimethylpyrazine and aqueous hydrogen peroxide (g / ml) ratio is 7:33, the weight volume (g / ml) ratio of 2,3,5-trimethylpyrazine and glacial acetic acid is 1:5;

[0043] S2. Preparation of 2-chloro-3,5,6-trimethylpyrazine: mix the 1-oxo-2,3...

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Abstract

The invention discloses a synthetic method of 2-ethyl-3,5,6-trimethyl pyrazine. The method comprises the following steps of 1, 1-oxo-2,3,5-trimethyl pyrazine preparation, wherein 2,3,5-trimethyl pyrazine and glacial acetic acid are mixed to be uniform, an aqueous hydrogen peroxide solution is added, heating is conducted, heat-preservation stirring is conducted, glacial acetic acid is removed, the pH is adjusted, extraction is conducted, dichloromethane is removed, 1-oxo-2,3,5-trimethyl pyrazine is obtained, and the aqueous hydrogen peroxide solution is added for three times with the same adding quantity; 2, 2-chlorine-3,5,6-trimethyl pyrazine preparation, wherein 1-oxo-2,3,5-trimethyl pyrazine obtained in the first step and phosphorus oxychloride are mixed to be uniform, heating is conducted, heat-preservation stirring is conducted, a solution A is obtained and added into crushed ice to be mixed to be uniform for cooling, the pH is adjusted, extraction is conducted, dichloromethane is removed, and 2-chlorine-3,5,6-trimethyl pyrazine is obtained; 3, 2-ethyl-3,5,6-trimethyl pyrazine preparation.

Description

technical field [0001] The invention relates to the technical field of preparation of 2-ethyl-3,5,6-trimethylpyrazine, in particular to a synthesis method of 2-ethyl-3,5,6-trimethylpyrazine. Background technique [0002] Ligustrazine is a colorless needle crystal, its chemical name is 2,3,5,6-tetramethylpyrazine, referred to as tetramethylpyrazine, its molecular weight is 138.20, and its boiling point is 190°C. Has a special odor, hygroscopicity, easy sublimation. Soluble in hot water, petroleum ether, soluble in chloroform, dilute hydrochloric acid, slightly soluble in ether, insoluble in cold water. It has relatively good pharmacological effects such as dilating blood vessels, mildly lowering blood pressure, inhibiting platelet adhesion and aggregation and thrombus formation, and inhibiting the proliferation of smooth muscle cells and fibroblasts. Now it is mainly used clinically to treat occlusive vascular diseases, such as cerebral embolism, coronary heart disease, ang...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D241/12
CPCC07D241/12
Inventor 王康林张成栋黄志生李海剑王高进
Owner HEFEI PINGGUANG PHARMA