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Method for preparing 5-methylprazine-2-carboxylic acid

A technology of methylpyrazine and pyrazine dicarboxylic acid, applied in chemical instruments and methods, organic decomposition, organic chemistry, etc., can solve the problems of harsh conditions, unfavorable large-scale production, and high temperature, and achieves less by-products, green environmental protection Mild conditions and highly selective effects

Active Publication Date: 2011-02-02
LIAONING ASYMCHEM LAB CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has harsh conditions, although it is a water phase reaction, but the temperature is high, which is not conducive to large-scale production

Method used

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  • Method for preparing 5-methylprazine-2-carboxylic acid
  • Method for preparing 5-methylprazine-2-carboxylic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Add 80g of 5-methyl-2,3-pyrazinedicarboxylic acid to the 2L four-necked bottle And 0.96kg saturated saline (10ml / g), warming up to 110oC reflux reaction for 10h. When the reaction is carried out until the HPLC shows that the conversion rate is 91%, it is cooled to room temperature, and the filtrate is filtered with 1.6kg butanone (25mL / g), the organic phase is combined and concentrated, cooled and crystallized in an ice-water bath, and the product is obtained by suction filtration 33.5 g. HPLC purity: 98%, isomer impurity content: 1.1%, yield: 55%.

Embodiment 2

[0019] Add 36g of 5-methyl-2,3-pyrazinedicarboxylic acid to the 2L four-necked bottle And 349g saturated brine (8ml / g), warming up to 108oC reflux reaction 8h. When the reaction is carried out until the HPLC shows that the conversion rate is 92%, it is cooled to room temperature, suction filtered, and the filtrate is concentrated with 524g butanone (18mL / g), the organic phase is combined, cooled and crystallized in an ice-water bath, and the product 15.3 g. HPLC purity: 98%, isomer impurity content: 0.7%, yield: 56.2%.

Embodiment 3

[0021] Add 54g of 5-methyl-2,3-pyrazinedicarboxylic acid to the 2L four-necked bottle And 327g saturated brine (5ml / g), warming up to 105oC reflux reaction 8h. When the reaction is carried out until the HPLC shows that the conversion rate is 90%, it is cooled to room temperature, suction filtered, and the filtrate is concentrated with 655g butanone (15mL / g), the organic phase is combined, cooled and crystallized in an ice-water bath, and the product 22.5 is obtained by suction filtration. g. HPLC purity: 98%, isomer impurity content: 2.0%, yield: 55%.

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Abstract

The invention provides a method for preparing 5-methylprazine-2-carboxylic acid. The preparation method comprises the steps: using 5-methyl-2and3- pyrazine 2-carboxylic acid as raw material, carrying The invention provides a method for preparing 5-methylprazine-2-carboxylic acid. The preparation method comprises the steps: using 5-methyl-2and3- pyrazine 2-carboxylic acid as raw material, carryingout photophobism reaction in a saturated saline solution, and obtaining 5-methylprazine-2-carboxylic acid as a final product. The preparation method optimizes the process from the source on the basisout photophobism reaction in a saturated saline solution, and obtaining 5-methylprazine-2-carboxylic acid as a final product. The preparation method optimizes the process from the source on the basisof the principle of water decarboxylation, thereby being a method for effective decarboxylation in a saline solution at lower temperature. Moreover, in the preparation method, no organic solvent is adof the principle of water decarboxylation, thereby being a method for effective decarboxylation in a saline solution at lower temperature. Moreover, in the preparation method, no organic solvent is added in the chemical reaction, no pollution is generated, the condition is mild, the reaction in the whole technological process has no high temperature, high selectivity and few by-products, thus theded in the chemical reaction, no pollution is generated, the condition is mild, the reaction in the whole technological process has no high temperature, high selectivity and few by-products, thus thepreparation method is a simple and available pollution-free method which has the capability of large-scale production.preparation method is a simple and available pollution-free method which has the capability of large-scale production.

Description

(1) Technical field: [0001] The invention relates to a preparation method of 5-methylpyrazine-2-carboxylic acid. (two) background technology: [0002] The decarboxylation reaction is generally accomplished by taking advantage of the thermal instability of the compound through vacuum decarboxylation, solvent decarboxylation, and high-pressure decarboxylation in aqueous media. [0003] Vacuum decarboxylation is the use of vacuum to remove the carbon dioxide generated after the reaction, so that the reaction proceeds in the positive direction. This method needs to be equipped with special equipment, and the initial production investment is relatively large. [0004] Solvent decarboxylation is to use solvents with higher boiling points such as xylene and trimethylbenzene, and carry out decarboxylation at about 140-180 °C. The disadvantage of this method is that the cost is high, a large amount of organic solvent is consumed, there are many by-products and it is difficult to re...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D241/24C07B37/06
Inventor 洪浩陈迥陈朝勇
Owner LIAONING ASYMCHEM LAB CO LTD
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