Preparation method of 4-aminopyridine compound

An aminopyridine and compound technology, applied in the field of organic compound preparation, can solve problems such as low preparation efficiency and complicated operation, and achieve the effects of simple preparation method, high reaction efficiency, good universality and tolerance

Pending Publication Date: 2021-02-05
NANJING LYNSCI CHEM
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Therefore, the technical problem to be solved in the present invention is to overcome the defects of low preparation efficiency and complicated operation of 4-aminopyridine compounds in the prior art, thereby providing a preparation method of 4-aminopyridine compounds, through a simple operation method , to prepare 4-aminopyridine compounds with high yield and high purity

Method used

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  • Preparation method of 4-aminopyridine compound
  • Preparation method of 4-aminopyridine compound

Examples

Experimental program
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Effect test

Embodiment 1

[0022] Preparation method of 4-amino-3-chloro-2,6-difluoropyridine

[0023] Synthesis of 3,5-dichloro-2,4,6-trifluoropyridine: Mix 250g of pentachloropyridine, 190g of anhydrous potassium fluoride and 600mL of sulfolane, stir and react at 150°C for 2h, cool down to room temperature, and monitor the raw materials by sampling After complete conversion, the reaction solution was poured into 3L of ice water and extracted with dichloromethane. The organic phase was washed with water and saturated sodium chloride solution successively, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained crude product was purified by rectification to obtain 174.5 g of a colorless liquid, which was 3,5-dichloro-2,4,6- Trifluoropyridine, GC detection content 98.7%, yield 87%.

[0024] Synthesis of 4-amino-3,5-dichloro-2,6-difluoropyridine: Cool 500mL of 25% ammonia water to 0°C, slowly add 100g of 3,5-dichloro-2,4,6-tri Fluoropyridine, a white solid gradually pr...

Embodiment 2

[0027] The preparation method of 4-amino-2,6-difluoropyridine

[0028] Add 40g of 4-amino-3,5-dichloro-2,6-difluoropyridine, 86g of potassium phosphate, 4g of 10% palladium carbon catalyst (water content 54%) and 300mL of 50% ethanol aqueous solution into the hydrogenation kettle, and successively use nitrogen, Replace with hydrogen, then react under 0.5MPa hydrogen pressure at 65°C for 8 hours, cool down to room temperature, evaporate most of the solvent under reduced pressure, then add 150mL of water to dilute, filter with suction, wash the filter cake fully with water, and then recrystallize with 15mL of 50% ethanol aqueous solution , to obtain 24 g of white flaky solid, which is 4-amino-2,6-difluoropyridine, with an HPLC content of 98.5% and a yield of 92%.

Embodiment 3

[0030] Preparation method of 4-amino-2,5,6-trifluoropyridine

[0031] Synthesis of 3-chloro-2,4,5,6-tetrafluoropyridine: Mix 70g of 3,5-dichloro-2,4,6-trifluoropyridine, 22g of anhydrous potassium fluoride and 150mL of sulfolane at 180°C Stir the reaction for 2.5 h, lower to room temperature, take a sample to monitor the complete conversion of the raw material, pour the reaction solution into 1 L of ice water, and extract with dichloromethane. The organic phase was washed with water and saturated sodium chloride solution successively, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained crude product was purified by rectification to obtain 46.5 g of a colorless liquid, which was 3-chloro-2,4,5,6-tetra Fluoropyridine, GC content 98.3%, yield 72%.

[0032] Synthesis of 4-amino 3-chloro-2,5,6-trifluoropyridine: Cool 200mL of 25% ammonia water to 0°C, slowly add 40g of 3-chloro-2,4,5,6-tetrafluoropyridine dropwise, A white solid gradually pr...

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Abstract

The invention discloses a preparation method of a 4-aminopyridine compound. The preparation method comprises the following steps: adding a 4-amino- 3-chloropyridine compound or a 4-amino-3, 5-dichloropyridine compound, potassium phosphate and a catalyst into a solvent, and reacting at 0-10 MPa and 0-100 DEG C for 4-12 hours. According to the preparation method of the 4-aminopyridine compound, therelated raw materials are easy to obtain or self-make, the cost is low, the preparation method is simple, the reaction efficiency is high, the raw material cost is low, and byproducts have economic value; meanwhile, the reaction involved in the invention has good universality and tolerance to functional groups.

Description

technical field [0001] The invention relates to the technical field of organic compound preparation, in particular to a preparation method of 4-aminopyridine compounds. Background technique [0002] 4-Aminopyridine compounds are a very important class of chemical raw materials, widely used in scientific research, synthetic pesticides and production of pharmaceutical products. In scientific research, such compounds can be used to construct more complex target compounds by participating in a wide variety of organic chemical reactions. [0003] Among the currently known synthetic methods, most of the 3- or 3,5-substituted 4-aminopyridines with hydrogen atoms are prepared by the following two methods: 1. Using the corresponding 4-halopyridines The compound is prepared by reacting with ammonia under high pressure; 2. It is obtained by hydrogenation dechlorination of 4-aminopyridine compounds with 3-chlorination or 3,5-dichlorination respectively. The first method needs to prepa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/73
CPCC07D213/73
Inventor 陈正伟征玉荣何彬张莉笋于传宗王维刘亮
Owner NANJING LYNSCI CHEM
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