Preparation method of 4,6-dichloropyrimidine

A technology for dichloropyrimidine and dihydroxypyrimidine, which is applied in the field of preparation of 4,6-dichloropyrimidine, can solve problems such as environmental pollution and control difficulties, and achieve the effects of avoiding recovery and reuse, avoiding cumbersome processes and avoiding waste.

Active Publication Date: 2014-01-29
CHONGQING UNISPLENDOUR CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method solves the problem of large amount of alkali consumption, it needs to add chlorine gas at a higher temperature, which is very difficult to control, and overflowing chlorine gas will pollute the environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] In a four-neck flask equipped with a reflux condenser, a thermometer, a stirrer and a constant pressure dropping funnel, add 4,6-dihydroxypyrimidine (114g, content 98%, 1mol), phosphorus oxychloride (311.5g, Content 99%, 2.01mol) and phosphorus pentachloride (421.3g, 99%, 2.005mol), that is, the molar ratio of phosphorus oxychloride to 4,6-dihydroxypyrimidine is 2.01, phosphorus pentachloride to 4,6 - The molar ratio of dihydroxypyrimidine is 2.005. Stir and mix 4,6-dihydroxypyrimidine, phosphorus oxychloride and phosphorus pentachloride evenly, and react at a temperature of 105-110°C for 2 hours, and the content of 4,6-dihydroxypyrimidine is 0.7% according to HPLC analysis , 4,6-dichloropyrimidine content was 98.9%, the reaction was completed, and the reaction mixture was cooled to 30°C. The reaction mixture was distilled under reduced pressure to obtain 570 g of phosphorus oxychloride (content 99%), with a recovery rate of 91.9%; the reaction mixture after recovery o...

Embodiment 2

[0027] In a four-neck flask equipped with a reflux condenser, a thermometer, a stirrer and a constant pressure dropping funnel, add 4,6-dihydroxypyrimidine (114g, content 98%, 1mol) and phosphorus oxychloride (310g, Content 99%, 2mol) mixed, under the condition of temperature control 50-55 ℃, phosphorus pentachloride is added in batches to react, the total amount of phosphorus pentachloride added is 2.01mol (422.77g, 99%), that is, oxytrichloride The molar ratio of phosphorus to 4,6-dihydroxypyrimidine is 2, and the molar ratio of phosphorus pentachloride to 4,6-dihydroxypyrimidine is 2.01. HPLC analysis showed that the content of 4,6-dihydroxypyrimidine was 0.5%, and the content of 4,6-dichloropyrimidine was 99.3%. The reaction was completed, and the reaction mixture was cooled to 25°C. The reaction mixture was distilled under reduced pressure to obtain 572g of phosphorus oxychloride (content 99%), the recovery rate was 92.3%; the reaction mixture after recovery of phosphorus...

Embodiment 3

[0029] In a four-necked flask equipped with a reflux condenser, thermometer, stirrer and constant pressure dropping funnel, add 4,6-dihydroxypyrimidine (114g, content 98%, 1mol) and phosphorus oxychloride (774.4g , content 99%, 5mol) mixed, under the condition of temperature control 60-65 ℃, phosphorus pentachloride is added in batches to react, the total amount of phosphorus pentachloride added is 2.008mol (422.3g, 99%), that is, trichloride The molar ratio of oxon to 4,6-dihydroxypyrimidine is 5, and the molar ratio of phosphorus pentachloride to 4,6-dihydroxypyrimidine is 2.008. HPLC analysis showed that the content of 4,6-dihydroxypyrimidine was 0.8%, and the content of 4,6-dichloropyrimidine was 98.6%. The reaction was completed, and the reaction mixture was cooled to 20°C. The reaction mixture was distilled under reduced pressure to obtain 997g of phosphorus oxychloride (content 99%), with a recovery rate of 92%; the reaction mixture after recovery of phosphorus oxychlor...

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PUM

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Abstract

The invention discloses a preparation method of 4,6-dichloropyrimidine. The preparation method comprises the following steps: 1) mixing 4,6-dyhydroxy pyrimidine, phosphorus oxychloride and phosphorus pentachloride, controlling the temperature to be 50-110 DEG C, reacting, stopping the reaction until the content of 4,6-dyhydroxy pyrimidine is lower than 1%, cooling a reactant mixture to a temperature lower than 30 DEG C; or, mixing 4,6-dyhydroxy pyrimidine with phosphorus oxychloride, controlling the temperature to be 50-110 DEG C, adding phosphorus pentachloride batch by batch, reacting, stopping the reaction until the content of 4,6-dyhydroxy pyrimidine is lower than 1%, cooling the reactant mixture to a temperature lower than 30 DEG C; 2) carrying out reduced pressure distillation on the reactant mixture to recover phosphorus oxychloride; and 3) purifying the reactant mixture from which phosphorus oxychloride is recovered in step 2), thus obtaining 4,6-dichloropyrimidine. Namely, the invention provides the method for preparing 4,6-dichloropyrimidine without utilizing an organic alkali, by which, a tedious process of recovering and recycling the organic alkali is avoided; phosphorus oxychloride can be recycled, therefore the waste of resources is avoided; and furthermore, a large amount of phosphorus-containing waste solution and waste slag is not likely to generate.

Description

technical field [0001] The invention belongs to the technical field of organic chemistry, in particular to a preparation method of 4,6-dichloropyrimidine. Background technique [0002] 4,6-Dichloropyrimidine is an important intermediate in the synthesis of sulfa drugs and fungicide azoxystrobin. There have been many reports in the literature on its preparation methods. The most common method is: react 4,6-dihydroxypyrimidine with tertiary amines such as triethylamine, pyridine, N,N-dimethylaniline, and phosphorus oxychloride at a certain temperature, and distill the resulting reaction mixture under reduced pressure , after recovering excess phosphorus oxychloride, pour it into ice water, extract with organic solvent, dry and dehydrate, recover the organic solvent to obtain 4,6-dichloropyrimidine; or add the reaction mixture to sodium hydroxide solution at low temperature and, then steam distillation, centrifugation, washing, and drying to obtain the product (Yang Guiqiu, P...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D239/30
CPCC07D239/30
Inventor 丁永良郑道敏刘佳范倩玉姚如杰朱丽利何咏梅李静
Owner CHONGQING UNISPLENDOUR CHEM
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