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Process of selective synthesizing 5-methyl pyrazine-2-carboxylic acid using 2,5-dimethyl pyrazine

A technology of dimethylpyrazine and methylpyrazine, applied in directions such as organic chemistry, can solve the problems of high product cost, increased consumption of potassium permanganate, and the process is limited by seasonality, and achieves low cost and simple product process. Effect

Inactive Publication Date: 2007-07-18
CHENGDU ORGANIC CHEM CO LTD CHINESE ACAD OF SCI
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Problems solved by technology

[0003] In the above process, the electrochemical method has large investment, high power consumption, and high product cost; the fermentation method has a high yield, but it is difficult to cultivate oxidative strains, and the process is subject to seasonal restrictions; CN1392143 uses o-phenylenediamine and aceglyoxal to prepare 5 -Methylpyrazine-2-carboxylic acid, needs to consume a large amount of potassium permanganate and sulfuric acid, produces a large amount of waste; Adopt the potassium permanganate direct oxidation 2 that has added inhibitor among CN1365974, one step of 5-dimethylpyrazine Synthesis of 5-methylpyrazine-2-carboxylic acid, the existence of inhibitor is to prevent potassium permanganate from continuing to oxidize 5-methylpyrazine-2-carboxylic acid, so the presence of inhibitor reduces 2,5- The conversion rate of dimethylpyrazine increases the consumption of potassium permanganate, and the by-product pyrazine-2,5-dicarboxylic acid is not easy to separate from the product

Method used

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  • Process of selective synthesizing 5-methyl pyrazine-2-carboxylic acid using 2,5-dimethyl pyrazine

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Embodiment Construction

[0017] 1. Single Nitrogen Oxidation

[0018] In a 1000ml reaction bottle, add 108g of 2,5-dimethylpyrazine, 450ml of water, 2.0g of sodium tungstate, and 2ml of sulfuric acid, add 114g of 30% hydrogen peroxide dropwise at 70°C for 2 hours, and continue to react at 70°C for 6 hours , to obtain 115.3 g of 2,5-dimethylpyrazine-1-oxide, with a yield of 93%.

[0019] 2, Preparation of 2-acetoxymethyl-5-methylpyrazine

[0020] In a 500ml flask, add 24.8g of 2,5-dimethylpyrazine-1-oxide, add 250ml of acetic anhydride, heat to reflux for 10h, recover the acetic anhydride and the generated acetic acid under reduced pressure, and obtain the residual oil 2-acetoxy Methyl-5-methylpyrazine 28.5g, yield 86%.

[0021] 3. Hydrolytic oxidation

[0022] In a 500ml flask, add 16.6g of 2-acetoxymethyl-5-methylpyrazine, add 50ml and 0.5g of sodium hydroxide, control the temperature at 20-25°C, add dropwise 300ml of aqueous solution containing 15.8g of potassium permanganate, After dripping, ke...

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Abstract

This invention use 2,5- dimethyl pyrazine as raw materials, selectively synthesize 5-methyl pyrazine-2-carboxylic acid. Its technology is use 2,5 - dimethyl pyrazine as raw material, through oxidation of nitrogen and hydrogen peroxide, acetic anhydride acid oxidation, hydrolysis and oxidation process, gain 5-methyl pyrazine-2-carboxylic acid. HPLC analysis of their content is over 99%, with 0.1 mol / L of sodium hydroxide titration, content is not less 98%, melting point is not less than of 163 deg, the quality of medicine to meet glipizide, Acipimox requirements. The process is scheme simple, high-yield, low cost and suitable for industrial production.

Description

technical field [0001] The invention relates to a method for single and selective synthesis of 5-methylpyrazine-2-carboxylic acid by using 2,5-dimethylpyrazine as a raw material, belonging to the technical field of organic synthesis. Background technique [0002] 5-Methylpyrazine-2-carboxylic acid is a key intermediate in the synthesis of the third-generation diabetes drug glipizide and blood lipid-lowering drug acipimox. Its existing synthesis methods mainly include microbial synthesis, electrochemical oxidation and chemical synthesis. The electrochemical method needs to synthesize 2-methyl-5-hydroxymethylpyrazine by chemical method earlier, then adopts the synthetic 2-methylpyrazine-5-carboxylic acid (EP0316945,1989) by electrochemical method; , 5-dimethylpyrazine is raw material, in the fermenter of PH=7.0 and room temperature 30 ℃, cultivate Pseudomonas as only carbon source and energy source with p-xylene, Pseudomonas plays oxidation, The yield can reach 95% (US521397...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D241/24
Inventor 陶家林唐德金夏雨
Owner CHENGDU ORGANIC CHEM CO LTD CHINESE ACAD OF SCI
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