Method for synthesising 2,3-dichloropyridine

A technology of dichloropyridine and trichloropyridine, which is applied in the field of organic synthesis, can solve problems such as low yield, worrying industrialization prospects, and difficulty in obtaining 2-chloronicotinamide, and achieves the effect of simple and easy operation

Active Publication Date: 2017-03-22
JIANGSU ZHONGBANG PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Chinese patent application CN102086174A discloses a production method of 2,3-dichloropyridine, which uses 2-chloronicotinamide as a raw material to avoid the problem of many side reactions caused by 2-position chlorination, but 2 - Chloronicotinamide is not easy to obtain, so the industrialization prospect of this method is worrying
This method has no selectivity to 2-position and 6-position chlorine in the hydrogenation process, so there

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Example 1: Synthesis of 2,3-dichloropyridine.

[0023] 2,3,6-Trichloropyridine (18.2g, 0.1mol), RhH(CO)(Ph 3 P) 3 (0.455g), triethylamine (12.1g, 0.12mol) and methanol (182g) were put into the autoclave, and the air in the autoclave was replaced after sealing the autoclave, and hydrogen gas was introduced to a pressure of 60MPa, and reacted at 60°C until no Until the phenomenon of hydrogen absorption, the control in HPLC (2,3,6-trichloropyridine)≤1%; -A mixture of dichloropyridine and water, the temperature was lowered and suction filtered to obtain 14.5 g of 2,3-dichloropyridine, the purity (HPLC) was ≥98%, and the yield was 98%.

Embodiment 2

[0024] Example 2: Synthesis of 2,3-dichloropyridine.

[0025] 2,3,6-Trichloropyridine (18.2g, 0.1mol), RhH(CO)(Ph 3 P) 3 (0.455g), triethylamine (80.9g, 0.8mol) and ethanol (182g) are put into the autoclave, after sealing the autoclave, replace the air therein, feed hydrogen to a pressure of 100MPa, and react at 80°C until no Until the phenomenon of hydrogen absorption, the control in HPLC (2,3,6-trichloropyridine)≤1%; -A mixture of dichloropyridine and water, obtained 13.5 g of 2,3-dichloropyridine by suction filtration under reduced temperature, with a purity (HPLC)≥98%, and a yield of 91.2%.

Embodiment 3

[0026] Example 3: Synthesis of 2,3-dichloropyridine.

[0027] 2,3,6-Trichloropyridine (18.2g, 0.1mol), RhH(CO)(Ph 3 P) 3 (0.182g), triethylamine (10.1g, 0.1mol) and isopropanol (91g) are put into the autoclave, after sealing the autoclave, replace the air therein, feed hydrogen until the pressure is 100MPa, react at 80°C, Until there is no hydrogen absorption phenomenon, the control (2,3,6-trichloropyridine) in HPLC≤1%; A mixture of 2,3-dichloropyridine and water was obtained, and 12.2 g of 2,3-dichloropyridine was obtained by suction filtration under reduced temperature, with a purity (HPLC)≥98% and a yield of 82.4%.

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Abstract

The invention discloses a method for synthesising 2,3-dichloropyridine. The synthesis method disclosed by the invention specifically comprises the following steps: adding 2,3,6-trichloropyridine, hydridocarbonyltris(tri-phenylphosphine)rhodium, triethylamine and a solvent into an autoclave, carrying out airtight ventilation, charging hydrogen until the pressure is 50-100MPa, reacting at 50-80 DEG C until a hydrogen absorption phenomenon disappears, removing the solvent in a manner of reduced pressure distillation, adding water and then distilling out the mixture of 2,3-dichloropyridine and water in a manner of constant-pressure water vapour distillation, and obtaining 2,3-dichloropyridine through cooling and suction filtration. A dechloridation reaction can be selectively carried out on 6-site chlorine atom because a catalyst with a large volume is adopted, and then 2,3-dichloropyridine with both ideal purity and yield is obtained; and the used raw materials are relatively easily-available, the operation process is simple, convenient and practicable, and a great industrialized application prospect is achieved.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis and relates to a method for synthesizing 2,3-dichloropyridine by utilizing 2,3,6-trichloropyridine. Background technique [0002] 2,3-Dichloropyridine is an important fine chemical intermediate, which can be used as a key intermediate in the synthesis of a new type of insecticide, sulfbendamide, and is widely used in many fields such as medicine and pesticides. [0003] Chinese patent application CN103570609A discloses a method for preparing 2,3-dichloropyridine, which uses nicotinamide as raw material to react with sodium hypochlorite to prepare 3-aminopyridine, and then reacts hydrochloric acid and hydrogen peroxide to obtain 2-chloro-3-amino Pyridine, and finally the target product was obtained by Sandmeyer reaction. This method has more side reactions and lower yield. [0004] Chinese patent application CN102086174A discloses a production method of 2,3-dichloropyridine, which uses ...

Claims

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Application Information

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IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 李维思钱勇陈涛章月唐景玉
Owner JIANGSU ZHONGBANG PHARMA
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