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Preparation method of 2-bromo-3-methoxypyridine

A technology of methoxypyridine and nitro, which is applied in the field of preparing 2-bromo-3-methoxypyridine, can solve the problems of unsuitability for large-scale industrial production, difficulty in product separation and purification, harsh reaction conditions, etc., and achieve post-processing Easy separation and purification, novel reaction route and low cost

Active Publication Date: 2015-05-13
BEIJING GREENCHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the raw materials of this process are expensive, and the commonly used methylating reagents are dimethyl sulfate and methyl iodide. Among them, dimethyl sulfate is highly toxic and has high toxicity. Although methyl iodide has low toxicity, it is very unstable and expensive. More expensive, and the separation and purification of the product is difficult, the reaction conditions are harsh, and it needs to be operated under anhydrous and oxygen-free conditions. When dealing with anhydrous solvents, the cost is high and the risk is high, so it is not suitable for large-scale industrial production

Method used

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  • Preparation method of 2-bromo-3-methoxypyridine
  • Preparation method of 2-bromo-3-methoxypyridine

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preparation example Construction

[0022] The synthetic route of the preparation method of the present invention is as follows:

[0023]

[0024] The preparation method of 2-bromo-3-methoxypyridine provided by the present invention will be described in detail below:

[0025] Add 2-nitro-3-methoxypyridine represented by structural formula (I) and an appropriate amount of organic acid solvent into the reaction vessel, stir to dissolve all the 2-nitro-3-methoxypyridine, and wait until the raw materials are completely After dissolving, add brominating agent such as hydrobromic acid, wherein the molar ratio of 2-nitro-3-methoxypyridine to brominating agent is 1:2-3, preferably 1:2-2.5; slowly increase the temperature to 100-140 ℃, reaction for 4-7 hours, preferably reaction temperature of 120-130 ℃, reaction for 5-6 hours. After the reaction is completed, the heating is stopped, and the stirring is continued to cool to room temperature.

[0026] After the reaction solution was distilled under reduced pressure to distill ...

Embodiment 1

[0035] Add 6g of 2-nitro-3-methoxypyridine and 18mL of acetic acid into the reaction flask, stir to dissolve all of them, add 15.8g of hydrobromic acid with a concentration of 40% by mass after the raw materials are completely dissolved, and slowly raise the temperature to 120 ℃, react for 5 hours, stop heating after the reaction is completed, continue to stir to cool to room temperature.

[0036] After the reaction solution was distilled under reduced pressure to distill most of the solvent, the vacuum distillation was stopped. At this time, a yellow solid precipitated out. Filtered. After the filter cake was washed twice with ethyl acetate, the filter cake was dissolved in a small amount of water, and saturated sodium carbonate was added. The pH of the aqueous solution was adjusted to 7-8, a white solid precipitated, filtered, the solid was washed twice with water, and then filtered. After drying, 6.4 g of solid 2-bromo-3-methoxypyridine was obtained. The calculated yield was 88...

Embodiment 2

[0038] Add 10g of 2-nitro-3-methoxypyridine and 30mL of acetic acid into the reaction flask and stir to dissolve them. After the raw materials are completely dissolved, add 28.9g of hydrobromic acid with a concentration of 40% by mass, and slowly increase the temperature to 125 ℃, react for 6h, stop heating after the reaction is completed, continue to stir to cool to room temperature.

[0039] After the reaction solution was distilled under reduced pressure to remove most of the solvent, the vacuum distillation was stopped. At this time, a yellow solid precipitated out. Filtered. After the filter cake was washed twice with ethyl acetate, the filter cake was dissolved in a small amount of water, and saturated hydrogen carbonate was added. Adjust the pH of the sodium aqueous solution to 7-8, a white solid precipitated out, filtered, washed the solid twice with water, and then filtered. After drying, 11.0g of solid 2-bromo-3-methoxypyridine was obtained, and the calculated yield was ...

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Abstract

The invention discloses a preparation method of 2-bromo-3-methoxypyridine. The method comprises the following steps: based on 2-nitro-3-methoxypyridine as a raw material, carrying out bromination reaction together with a brominating agent to directly replace nitro on a pyridine ring with a bromine atom, so as to obtain 2-bromo-3-methoxypyridine. The preparation method is novel in reaction route, mild in reaction conditions, easy to control, and easy in post-treatment, separation and purification; the obtained product is high in yield and purity. The preparation method is low in production cost, simple and safe to operate, and very suitable for large-scale industrial production.

Description

Technical field [0001] The invention relates to a method for preparing 2-bromo-3-methoxypyridine and belongs to the technical field of organic synthesis. Background technique [0002] 2-Bromo-3-methoxypyridine is an important pharmaceutical intermediate, mainly used for the synthesis of anti-estrogens, drug intermediates for the treatment of endometriosis and uterine fibroids and other related diseases, and for treatment Synthesis of cancer camptothecin drugs. [0003] At present, there are reports in the literature that the method for preparing 2-bromo-3-methoxypyridine is based on 2-bromo-3-hydroxypyridine as raw material, and methylation reaction with methylating reagents to obtain 2-bromo-3-methoxypyridine Pyridine. However, the raw materials for this process are expensive, and the commonly used methylation reagents are dimethyl sulfate and methyl iodide. Among them, dimethyl sulfate is highly toxic and has high toxicity. Although methyl iodide is low in toxicity, it is very ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/65
CPCC07D213/65
Inventor 宫宁瑞
Owner BEIJING GREENCHEM TECH
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