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New green technology for preparation of 2-chloronicotinic acid

A technology for chloronicotinic acid and nicotinic acid is applied in the field of green synthesis of 2-chloronicotinic acid to achieve the effects of short process flow, corrosion avoidance and mild reaction conditions

Inactive Publication Date: 2019-01-15
CHENGDU ORGANIC CHEM CO LTD CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The object of the present invention is to: provide a kind of with nicotinic acid as raw material, through N-oxidation and chlorination synthetic 2-chloronicotinic acid environmental protection, green synthesis new method, solve the environment-friendly synthesis of 2-chloronicotinic acid with nicotinic acid as raw material , cost, product quality and other issues

Method used

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  • New green technology for preparation of 2-chloronicotinic acid
  • New green technology for preparation of 2-chloronicotinic acid
  • New green technology for preparation of 2-chloronicotinic acid

Examples

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Effect test

Embodiment 1

[0027] Add 100ml of water, 100g of nicotinic acid, and 0.66g of molybdenum acid to the three-necked flask in sequence, and raise the temperature to 92°C. After the temperature stabilizes, start to add 104ml of hydrogen peroxide dropwise for 3 hours at a constant speed. Niacin content < 0.5%, drop to 0-5°C after heat preservation, stir for 0.5h, filter, the mother liquor will be reused in the next batch of oxidation reaction, and the filter cake is vacuum-dried at 60°C to obtain 108.7g of white crystalline powder N-oxidized nicotinic acid, Yield 97.4% [HPLC content 99.8%, moisture 0.22%, mp 261.4-261.6°C (260-262°C in literature)].

[0028] Add 146ml of phosphorus oxychloride to the three-necked flask, stir in an ice bath and cool down to 10°C, start to slowly add 32g (0.23mol) of N-oxidized nicotinic acid, then add 36ml of triethylamine (0.26mol) dropwise at 15°C, and dropwise The temperature was raised to 100°C with a uniform gradient for 6 hours.

[0029] The above reaction...

Embodiment 2

[0031] Add 100ml of N-oxidized nicotinic acid mother liquor, 100g of nicotinic acid, and 0.66g of molybdic acid in sequence to the three-necked flask, raise the temperature to 92°C, and start adding 104ml of hydrogen peroxide dropwise after the temperature stabilizes, add dropwise for 3 hours at a constant speed, and keep warm at 95°C after the dropwise addition is completed 3h, TLC detects that the content of niacin is <0.5%. After the heat preservation, it is lowered to 0-5°C, stirred for 0.5h, filtered, and the mother liquor is recycled for the next batch of oxidation reaction. The filter cake is vacuum-dried at 60°C to obtain white crystalline powder N-oxide fume Acid 111.7g, yield 99.6% [HPLC content 99.8%, moisture 0.21%, mp 261.4-261.6°C (document 260-262°C)].

[0032] Add a total of 146ml of recovered phosphorus oxychloride and fresh phosphorus oxychloride to the three-necked flask, stir in an ice bath and cool down to 10°C, start to slowly add 32g of N-oxidized nicotin...

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Abstract

The invention relates to a new green technology for preparation of 2-chloronicotinic acid. The technology includes: adopting nicotinic acid (I) as the raw material, conducting hydrogen peroxide N-oxidation under the action of a catalyst in a water system to obtain nicotinic acid N-oxide (II), then under the action of organic base, conducting phosphorus oxychloride chlorination to synthesize 2-chloronicotinyl chloride (III), and then performing hydrolysis and refining to obtain 2-chloronicotinic acid (IV). The method avoids the use of benzene and acetic acid, has the advantages of short process, safety and environmental protection, good product quality and high yield, is an environment-friendly green synthetic route, and is suitable for industrial production.

Description

technical field [0001] The invention belongs to the fields of medicine, chemical industry and pesticide, and relates to a green synthesis method of 2-chloronicotinic acid. Background technique [0002] 2-Chloronicotinic acid is mainly used in the new high-efficiency herbicides Nicosulfuron and Diflufenican, the new systemic fungicide Boscalid, antibacterial agents and anticancer drugs Synthesis of 2-chloropyridine-3-carbonyl-nitrogen-containing heterocyclic compounds and synthesis of pesticides and pharmaceutical intermediates such as HIV reverse transcriptase inhibitor Nevirapine. The research on 2-chloronicotinic acid started abroad as early as the 1970s. The earliest patent was applied by Lonza Company in Switzerland in 1977, and most of the patents are from Japan, such as Japan Koei Chemical, Japan Organic Synthesis and other well-known companies have applied for patents (JP5914459). However, domestic articles and patent reports (CN101367760A, CN101117332A) on the rese...

Claims

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Application Information

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IPC IPC(8): C07D213/80C07D213/803
CPCC07D213/80C07D213/803
Inventor 王立新徐小英王斐英邓聪迩彭林万文娟
Owner CHENGDU ORGANIC CHEM CO LTD CHINESE ACAD OF SCI
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