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Preparation method of 2,6-dichloropyridine

A dichloropyridine, 20min technology, applied in the field of intermediate synthesis, can solve the problems of large amount of acid and hydrogen peroxide, high reaction conditions, etc., and achieve the effect of no side reaction, high reaction yield and easy operation

Inactive Publication Date: 2022-01-25
ITIC MEDCHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, there are many methods for preparing pyridine N-oxygen compounds by oxidation of pyridine compounds. The most used method is hydrogen peroxide oxidation without catalyst or with catalyst, followed by m-chloroperoxybenzoic acid oxidation. The reaction conditions of the first method are: High, the amount of acid and hydrogen peroxide used is large, and a large amount of waste water is generated after treatment. The second method, the raw material of m-chloroperoxybenzoic acid is expensive

Method used

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  • Preparation method of 2,6-dichloropyridine
  • Preparation method of 2,6-dichloropyridine
  • Preparation method of 2,6-dichloropyridine

Examples

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Embodiment 1

[0017] A kind of preparation method of 2,6-dichloropyridine, comprises the following steps: the 2,6-dichloropyridine of 50.0g and 0.067mol is dissolved in the mixture that the trifluoroacetic acid of 150mL and the 30% hydrogen peroxide of 25mL form, in 150W-250W microwave power, heat at 28-32°C for 20 minutes; add saturated sodium thiosulfate solution to the above solution until the hydrogen peroxide is completely exhausted; add an appropriate amount after stripping the mother liquor to remove water and excess trifluoroacetic acid dichloromethane extraction, liquid separation, and precipitation to obtain the final product off-white solid 2,6-dichloropyridine-N-oxide, and the specific reactions are as follows:

[0018]

[0019] Wherein, 50.0 g and 0.067 mol of the 2,6-dichloropyridine were dissolved in a mixture of 150 mL of trifluoroacetic acid and 25 mL of 30% hydrogen peroxide, and heated at 30° C. for 20 min at 200 W microwave power.

[0020] Wherein, when adding the sat...

Embodiment 2

[0026] A kind of preparation method of 2,6-dichloropyridine, comprises the following steps: the 2,6-dichloropyridine of 50.0g and 0.067mol is dissolved in the mixture that the trifluoroacetic acid of 150mL and the 30% hydrogen peroxide of 25mL form, in 150W-250W microwave power, heat at 28-32°C for 20 minutes; add saturated sodium thiosulfate solution to the above solution until the hydrogen peroxide is completely exhausted; add an appropriate amount after stripping the mother liquor to remove water and excess trifluoroacetic acid dichloromethane extraction, liquid separation, and precipitation to obtain the final product off-white solid 2,6-dichloropyridine-N-oxide, and the specific reactions are as follows:

[0027]

[0028] Wherein, 50.0 g and 0.067 mol of the 2,6-dichloropyridine were dissolved in a mixture of 150 mL of trifluoroacetic acid and 25 mL of 30% hydrogen peroxide, and heated at 32° C. for 20 min at 210 W microwave power.

[0029] Wherein, when adding the sat...

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Abstract

The invention discloses a preparation method of 2,6-dichloropyridine. The preparation method comprises the following steps: dissolving 50.0 g of 2,6-dichloropyridine and 0.067 mol of 2,6-dichloropyridine in a mixture consisting of 150 mL of trifluoroacetic acid and 25 mL of 30% hydrogen peroxide, and irradiating for 20 minutes at the microwave power of 150W-250W and the temperature of 28-32 DEG C for heating; adding a saturated sodium thiosulfate solution into the solution until hydrogen peroxide is completely exhausted; and desolventizing the mother liquor to remove water and excessive trifluoroacetic acid, and then adding a proper amount of dichloromethane for extraction, liquid separation and desolventizing to obtain the final product namely white-like solid 2,6-dichloropyridine-N-oxide. The preparation method of the drug intermediate 2,6-dichloropyridine is reasonable in whole process flow design, mild in condition, simple and convenient to operate, easily available in raw materials and high in generation efficiency, and is very suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to the technical field of intermediate synthesis, in particular to a preparation method of 2,6-dichloropyridine. Background technique [0002] Pyridine N-oxides are an important class of pyridine derivatives. These N-oxides not only exist in natural products, but also are important structural features of many biologically active compounds. N-oxides have many special properties and chemical reactions. For example, the nitrification reaction is quite easy, and it is reversed at the para position; it is reacted at the 2- or 4-position by the action of a chlorinating agent such as phosphorus oxychloride, and the oxygen atom is removed at the same time; the chlorine at the 2-position or 4-position Or the nitro group is easily replaced by other affinity reagents. In addition, the oxygen atom of pyridine N-oxide is also easily removed by the action of trivalent phosphorus reagent, so pyridine N-oxide is an important intermediate for the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 孙号闫永平胡海威丁靓
Owner ITIC MEDCHEM CO LTD