Method for preparing tetramethyl pyrazine

A technology of ligustrazine and oxidizing agent, applied in the direction of organic chemistry and the like, can solve the problems of easy volatility, high production cost, large consumption of organic solvents, etc., and achieves the effects of small organic residues, low production cost, and reliable high yield.

Inactive Publication Date: 2009-11-04
张锋
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The extraction process of the above-mentioned ligustrazine is cumbersome, time-consuming, and consumes a large amount of organic solvents, leaving a large amount of organic solvents in the discharge, causing great environmental pollution.
Because ligustrazine has a low melting point and is easy to volatilize, atmospheric distillation will also distill out with water vapor, so the production cost is high and the yield is low

Method used

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  • Method for preparing tetramethyl pyrazine
  • Method for preparing tetramethyl pyrazine
  • Method for preparing tetramethyl pyrazine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Add 50g of 0.57mol of 3-hydroxy-2-butanone, 150ml of ethanol and 35.78g of 0.54mol of ammonium acetate into a 500ml round-bottomed flask, feed nitrogen, heat the oil bath at 79-89°C, and stir for 5-8 hours with magnetic force . After the stirring was completed, it was left open or magnetically stirred under oxygen condition for 12 hours. Add 31.45g of 0.36mol manganese dioxide, and stir magnetically for 1 to 2 hours. After the reaction is complete, use a Buchner funnel to filter the remaining manganese dioxide under reduced pressure. Under reduced pressure distillation, 29.12 g of ligustrazine needle crystals were collected by vacuum distillation. Use 50ml of ethyl acetate and 6 grams of activated carbon to re-distill under reduced pressure. The conditions of the reduced-pressure distillation are the same as those mentioned above. After drying, 28.32 g of 0.21 mol of Ligustrazine was received, with a yield of 72.50%.

[0026] Using 3-hydroxy-2-butanone and ammonium ac...

Embodiment 2

[0032] In the present invention, ketones such as butanone can be halogenated under acidic conditions to obtain acetoin, and then the method of Example 1 can be used to prepare ligustrazine. The specific method is: take 50g of butanone in a 250ml three-necked flask (equipped with a stirrer and a thermometer), add 80ml of hydrochloric acid and 120g of liquid bromine, stir, and heat to 50°C to 60°C with nitrogen gas for 2 to 3 minutes. hour, and then alkalized with sodium hydroxide to obtain acetoin mixture, passed through n-hexane for extraction, then dehydrated with anhydrous sodium sulfate to obtain acetoin, transferred to a flask, and prepared Ligustrazine by the method of Example 1.

[0033]

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Abstract

The invention relates to a preparation method of ligustrazine. It comprises the following steps: taking 3-hydroxy-2-butanone and ammonium acetate as raw materials, adding ethanol, feeding nitrogen, stirring for 5-8 hours in a hot bath; stirring for another 12 hours under air or oxygen conditions; adding an oxidizing agent , the weight ratio is oxidant: 3-hydroxyl-2-butanone=0.5~1:1, stirred for 1~2 hours; filtered to remove remaining oxidant; depressurized distillation to obtain Ligustrazine. The production rate of ligustrazine produced by the method of the invention is high. The amount of organic solvent used in the preparation process is small, which is beneficial to environmental protection, and has the advantages of low cost and simple operation.

Description

technical field [0001] The invention relates to a preparation method of medicine, in particular to a preparation method of tetramethylpyrazine with high yield. Background technique [0002] Ligustrazine (Ligustrazine) is a kind of alkaloid monomer isolated and purified from the rhizomes of Umbelliferae plants, and its chemical name is: 2,3,5,6-tetramethylpyrazine, referred to as tetramethyl Pyrazine (Tetramethyl Pyrazine TMP). It has antihypertensive and blood vessel expansion thrombolytic effects, and is mainly used clinically to treat ischemic cardiovascular and cerebrovascular diseases, such as cardiovascular and cerebrovascular diseases, cerebral embolism, coronary heart disease, angina pectoris, vasculitis, chronic pulmonary heart disease, chronic renal failure Wait. In recent years, it has been found that it has the effect of blocking calcium ion, and has the effect of chemotherapy sensitization and reversal of multidrug resistance of tumor cells. [0003] Ligustraz...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D241/12
Inventor 张锋
Owner 张锋
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