Chemical synthesis method of 3, 6-dichloro-2-aminopyridine

The technology of an aminopyridine and a synthesis method, which is applied in the synthesis field of halogenated aminopyridines, can solve the problems of harsh anhydrous and oxygen-free process conditions, harsh process operation conditions, and difficulty in large-scale production, and achieves good economic and social benefits. , the effect of good reaction selectivity and low manufacturing cost

Inactive Publication Date: 2013-01-16
XIHUA UNIV
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Problems solved by technology

The key step of this synthetic route is the second step. In this step reaction, a large amount of expensive n-butyllithium (the combination of n-butyllithium and N-(6-chloro-2-pyridyl)-pivalamide will be used. The molar ratio is 2.5), which makes the manufacturing cost high; at the same time, the use of n-butyl lithium makes the process anhydrous and oxygen-free operating conditio

Method used

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  • Chemical synthesis method of 3, 6-dichloro-2-aminopyridine
  • Chemical synthesis method of 3, 6-dichloro-2-aminopyridine

Examples

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[0025] Example 1

[0026] Add 45.6 grams (0.25 mol) of 2,3,6-trichloropyridine into a 1000ml pressure-resistant reactor, add 340 grams of 25% ammonia (containing 5 mol of ammonia), and add 4.56 grams of catalyst (the catalyst composition is 3.56 grams of chlorine Cuprous chloride, benzyl triethylammonium chloride 0.5 g, sodium iodide 0.5 g) and the reactor is sealed, heated to 120 ~ 125 ℃, react for 5 hours, release unreacted ammonia while hot, and wait for the reaction liquid After the release of ammonia gas, it was cooled to room temperature, 300ml of chloroform was added, stirred, filtered, the resulting filtrate was separated into phases, the organic phase was washed with water, dried over anhydrous magnesium sulfate, and the chloroform was removed under reduced pressure to obtain brown 3,6-dichloro-2-amino Crude pyridine. The crude product was recrystallized with 260 ml of toluene and dried to obtain 37.3 g of off-white 3,6-dichloro-2-aminopyridine with a content of 97.8% a...

Example Embodiment

[0027] Example 2

[0028] The catalyst is 3.56 grams of cuprous chloride, and the others are the same as in Example 1.

[0029] According to the operation in Example 1, 32.9 g of off-white 3,6-dichloro-2-aminopyridine was obtained, the content was 96.9%, and the yield was 80.9%.

Example Embodiment

[0030] Example 3

[0031] The catalyst is 4.06 grams (the composition of the catalyst is 3.56 grams of cuprous chloride and 0.5 grams of benzyltriethylammonium chloride).

[0032] According to the operation in Example 1, 36.3 g of off-white 3,6-dichloro-2-aminopyridine was obtained, the content was 97.2%, and the yield was 89.1%.

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Abstract

The invention discloses a chemical synthesis method of 3, 6-dichloro-2-aminopyridine. The target product 3, 6-dichloro-2-aminopyridine is obtained after simple post-processing through one-step reaction by using ammonization reagent and by using 2, 3, 6-trichloropyridine as a starting raw material, the yield is high and the product quality is high. Compared with the existing disclosed technique, the chemical synthesis method of 3, 6-dichloro-2-aminopyridine has the advantages that the reaction steps are fewer, the raw materials are easy to obtain, the energy consumption is low, the production cost is low, the technological intrinsic safety is high and the industrial production is easier to realized.

Description

technical field [0001] The invention relates to a synthesis method of halogenated aminopyridine, in particular to a synthesis method of 3,6-dichloro-2-aminopyridine. Background technique [0002] Halogenated aminopyridines are important fine chemical intermediates and are widely used in the fields of medicine and pesticides. 3,6-dichloro-2-aminopyridine is an important intermediate in the synthesis of S1P1 receptor agonists in medicine. Due to its relatively difficult synthesis, there are few reports on the synthesis of 3,6-dichloro-2-aminopyridine at home and abroad. Only the patent WO2009154775A1 discloses its synthesis method: the first step is to use 6-chloro-2-aminopyridine as a raw material , react with pivaloyl chloride under the condition of toluene as solvent and triethylamine as acid-binding agent to generate N-(6-chloro-2-pyridyl)-pivalamide. In the second step, N-(6-chloro-2-pyridyl)-pivalamide is used as raw material, tetrahydrofuran is used as solvent...

Claims

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Application Information

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IPC IPC(8): C07D213/73
Inventor 杨维清张园园倪小惠马梦林
Owner XIHUA UNIV
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