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Method for preparing 4, 6 dichloropyridine

A technology for dichloropyrimidine and dihydroxypyrimidine is applied in the field of preparing 4,6-dichloropyrimidine, and can solve the problems of high phosgene toxicity and limited use.

Active Publication Date: 2005-10-26
JIANGSU INST OF ECOMONES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, on the one hand, due to the high toxicity of phosgene, and on the other hand, some highly restrictive and legislative safety regulations on the transportation, storage and use of phosgene, the use of this method is greatly restricted.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Under the conditions of applying ice bath and stirring well, to the mixture of 4,6-dihydroxypyrimidine (34.2g, 0.3mol) and triphosgene (90g, 0.3mol) in dichloroethane (400ml), add dropwise Mixture of triethylamine (126ml, 0.9mol) and dichloroethane (150ml), the temperature is controlled below 5°C, and the addition is completed over 30 minutes. The resulting mixture was stirred for an additional 30 minutes below 5°C. Remove the ice bath and stir at room temperature for 1 hour, then at 60°C for 2 hours. The reactant was cooled, then washed with water (3×300ml), the aqueous layer was extracted with dichloroethane (2×100ml), the organic extracts were combined, washed with water (200ml), dried over anhydrous magnesium sulfate, and precipitated and dried to obtain 42.3 g of solid crystals of 4,6-dichloropyrimidine. The content by HPLC analysis was 99%, the yield corresponding to 93.6% of theory.

Embodiment 2

[0021] Under the condition of applying ice bath and stirring well, in the mixture of 4,6-dihydroxypyrimidine (34.2g, 0.3mol) and diphosgene (81g, 0.4mol) in dichloroethane (400ml), drop A mixture of triethylamine (112ml, 0.8mol) and dichloroethane (150ml) was added, the temperature was controlled below 5°C, and the addition was completed over 1 hour. The resulting mixture was stirred for an additional 30 minutes below 5°C. Remove the ice bath and stir at room temperature for 1 hour, then at 50°C for 1 hour, and at 70°C for 1 hour. The reactant was cooled, then washed with water (3×300ml), the aqueous layer was extracted with dichloroethane (2×100ml), the organic extracts were combined, washed with water (200ml), dried over anhydrous magnesium sulfate, and precipitated and dried to obtain 41.3 g of solid crystals of 4,6-dichloropyrimidine. The content by HPLC analysis was 98%, the yield corresponding to 90.7% of theory.

Embodiment 3

[0023] Under the conditions of applying ice bath and stirring well, into the mixture of 4,6-dihydroxypyrimidine (34.2g, 0.3mol) and triethylamine (126ml, 0.9mol) in dichloroethane (250ml), drop Triphosgene (90 g, 0.3 mol) dissolved in dichloroethane (300 ml) was added, the temperature was controlled below 5° C., and the addition was completed over 30 minutes. The resulting mixture was stirred for an additional 30 minutes below 5°C. Remove the ice bath and stir at room temperature for 1 hour, then at 60°C for 2 hours. The treatment was carried out as described in Example 1 to obtain 42.7 g of solid crystals of 4,6-dichloropyrimidine. The content by HPLC analysis was 99%, the yield corresponding to 94.5% of theory.

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PUM

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Abstract

The present invention relates to a method capable of using diphosgene or triphyosgene to chlorinate 4,6-dihydroxypyrimidine to obtain 4,6-dichloropyrimidine in the presence of proper alkali and a certain solvent or mixed solvent.

Description

field of invention [0001] The present invention relates to the conversion of 4,6-dihydroxypyrimidine to 4,6-dichloropyrimidine using diphosgene or triphosgene in the presence of a suitable base. 4,6-dichloropyrimidine can be used as a chemical intermediate in the pesticide and pharmaceutical industries, such as the preparation of the fungicide azoxystrobin, nucleoside analogs and compounds active in the central nervous system (CNS). Background technique [0002] Because of the widespread use and economic importance of 4,6-dichloropyrimidines, many methods have been developed for the synthesis of chlorinated pyrimidines, especially 4,6-dichloropyrimidines. [0003] WO 02 / 04428 (Chinese patent 01812416.X) discloses a reaction of organic amide (such as formamide, acetamide) and phosgene, or by the reaction of organic nitrile (such as butyronitrile) and hydrogen chloride to generate imidoyl chloride compound, imide A method for producing 4,6-dichloro...

Claims

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Application Information

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IPC IPC(8): C07D239/30
Inventor 孔繁蕾吴国平
Owner JIANGSU INST OF ECOMONES
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