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Method for one-step oxidation synthesis of 2-chloronicotinic acid

A technology of oxidative synthesis and chloronicotinic acid, which is applied in the direction of organic chemistry, can solve the problems of environmental pollution, long reaction route, and expensive oxidant, and achieve the effects of overcoming environmental pollution, easy separation, and meeting clean production

Inactive Publication Date: 2016-12-21
NANJING REDSUN BIOCHEM CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The purpose of the present invention is to overcome the deficiencies in the prior art that are easy to cause environmental pollution, long reaction routes and expensive oxidants, and provide a method for synthesizing 2-chloronicotinic acid by one-step oxidation. Environmental pollution problems, to meet the requirements of clean production

Method used

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  • Method for one-step oxidation synthesis of 2-chloronicotinic acid
  • Method for one-step oxidation synthesis of 2-chloronicotinic acid
  • Method for one-step oxidation synthesis of 2-chloronicotinic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0023] 80g (0.4mol) of 2-chloro-3-dichloromethylpyridine, 40g of water, 240g of acetonitrile, 48g of sodium carbonate, 1.6g of Ru / C (10% Ru, on a dry basis), were added to a 500ml autoclave for reaction In the device, after the feeding is completed, the kettle body is replaced by oxygen, and then filled with O 2 Until the pressure of the reactor is 3MPa, the temperature is raised to 100°C, the reaction starts, the pressure of the reactor drops, and O is continuously added. 2 , maintain the reaction pressure between 3.5-4MPa, when the pressure of the kettle remains constant, the reaction ends (reaction time 12h). Lower the temperature, recover the Ru / C catalyst by suction filtration for the next application, precipitate the filtrate to recover acetonitrile, add hydrochloric acid to the remaining liquid for acid analysis (adjust the pH value of the solution to 1), a large amount of white precipitates appear, suction filter, wash, dry, 59.8 g of white solid 2-chloronicotinic aci...

Embodiment 2

[0025] It was synthesized according to the method and conditions of Example 1, only the reaction temperature was adjusted to 140° C., and the polar organic solvent was 300 g of tetrahydrofuran. The reaction time was shortened to 4 hours, and 62.4 g of white solid 2-chloronicotinic acid was obtained after post-treatment. The purity of 2-chloronicotinic acid was 96.2%, and the yield was 95.4%.

Embodiment 3

[0027] Synthesized as in the method and conditions of Example 1, only changing the oxygen pressure to 4.5-5 MPa for reaction. The reaction time was shortened to 8 hours, and 61.9 g of 2-chloronicotinic acid was obtained as a white solid after post-treatment. The purity of 2-chloronicotinic acid was 97.9%, and the yield was 96.8%.

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Abstract

The invention discloses a method for one-step oxidation synthesis of 2-chloronicotinic acid. The method consists of: taking 2-chloro-3-dichloromethylpyridine as the raw material, adding alkali, using the mixture of water and a polar organic solvent as the solvent, adopting Ru / C as the catalyst, and carrying out oxygen oxidation to obtain a 2-chloronicotinic acid solution, then conducting acid precipitation, pumping filtration, washing and drying so as to obtain white solid powder 2-chloronicotinic acid. The method has the advantages of simple process, high yield up to 90% or more, use of oxygen as the oxidant, and environmental friendliness. The repeatedly applicable heterogeneous Ru / C catalyst is employed, and the product is easy to separate. The oxidation reaction system is a non-acidic system, overcomes the environmental pollution problem, and meets the requirements of clean production.

Description

technical field [0001] The invention belongs to the field of chemical organic synthesis, and in particular relates to a method for synthesizing 2-chloronicotinic acid through one-step oxidation. Background technique [0002] 2-Chloronicotinic acid is an important pesticide and pharmaceutical intermediate, mainly used in the preparation of the new high-efficiency herbicide nicosulfuron, the anti-inflammatory analgesic drug niflumic acid, pranoprofen and the HIV reverse enzyme inhibitor nevirapine. Therefore, the research on the preparation and production process of 2-chloronicotinic acid is of great significance. There are many ways to synthesize 2-chloronicotinic acid: [0003] (1) Using nicotinic acid or 3-cyanopyridine as raw material (US4144238, US40815, JP169672, Chinese Journal of Pharmaceutical Industry, 2004.35 (5), 267), oxidized with hydrogen peroxide, and then reacted with trichloroxygen under the catalysis of triethylamine React with phosphorus or phosphorus pen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/807C07D213/80
CPCC07D213/807C07D213/80
Inventor 陈新春王福军蒋剑华陈洪龙钟劲松
Owner NANJING REDSUN BIOCHEM CO LTD
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