Synthesis process of 4,6-dichloropyrimidine

A synthesis process, a technology of dichloropyrimidine, applied in directions such as organic chemistry, organic chemistry methods, etc., can solve the problems of cumbersome steps, low conversion rate of raw materials, large amount of solvent loss, etc., and achieves reasonable synthesis process, high product purity, and production cost. low effect

Inactive Publication Date: 2020-04-14
潍坊滨海石油化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The process of the first method is relatively simple, the main disadvantage is that a large amount of phosphorus-containing wastewater is generated, the wastewater treatment is difficult, the investment is large, and it does not conform to the concept of environmental protection
The second method greatly reduces the amount of wastewater, but a large amount of phosphorus oxychloride is used as a solvent in the process, and the reaction process will consume phosphorus oxychloride to generate impurities, resulting in waste of resources and increasing the cost of post-treatment
The third method does not produce a large amount of waste water during the reaction process, and the by-products are easy to treat and have high purity. However, because the reaction is a two-phase reaction, the conversion rate of raw materials is low, and there are also great difficulties in the use and transportation of raw materials.
The patent introduces dichloroethane as a solvent, and the solvent loss is relatively large in the process of desolventization and product crystallization and purification; dichloroethane is a highly toxic chemical and is very dangerous; in the preparation of 4,6-dichloropyrimidine In the reaction, the addition of thionyl chloride is excessive, because the boiling point of thionyl chloride is slightly lower than dichloroethane, it is not easy to separate the excess thionyl chloride earlier by distillation, and the excess oxychloride The sulfone needs to be digested, and the treatment method is generally to add alkaline water, or thermal decomposition to generate gas for reabsorption, which will generate a large amount of waste water; the product is purified by crystallization, and the steps are relatively cumbersome
[0006] Those of ordinary skill in the art generally believe that when 4,6-dihydroxypyrimidine is chlorinated by thionyl chloride to prepare 4,6-dichloropyrimidine, an additional organic solvent needs to be added to promote the reaction and increase product content and yield , only adding chlorinating agents and catalysts, without adding organic solvents, tends to reduce product content and yield

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] (1) Feeding

[0041] Put 1 mole of 4,6-dihydroxypyrimidine and 4 moles of thionyl chloride into the reaction flask;

[0042] (2) Add N,N-dimethylaniline dropwise

[0043] Weigh 2.1 moles of N,N-dimethylaniline into the constant pressure dropping funnel for later use, turn on the stirring and heating mantle, raise the temperature to 40°C, and slowly add N,N-dimethylaniline dropwise for 1 hour.

[0044] (3) insulation

[0045] Then keep warm at this temperature for 2h;

[0046] (4) Recovery of thionyl chloride

[0047] The reaction solution was transferred to a rectification device, and excess thionyl chloride was recovered by rectification under reduced pressure, and the recovered thionyl chloride content was 99%, and the recovery rate was 93.3%;

[0048] (5) Vacuum distillation

[0049] Continue vacuum distillation to obtain 4,6-dichloropyrimidine product with a content of 99.2% and a yield of 92.8%;

[0050] (6) Recovery of N,N-dimethylaniline

[0051] The remai...

Embodiment 2

[0055] (1) Feeding

[0056]Put 1 mole of 4,6-dihydroxypyrimidine and 6 moles of thionyl chloride into the reaction flask;

[0057] (2) Add N,N-dimethylaniline dropwise

[0058] Weigh 2.2 moles of N,N-dimethylaniline into the constant pressure dropping funnel for later use, turn on the stirring and heating mantle, raise the temperature to 50°C, and slowly add N,N-dimethylaniline dropwise for 2 hours;

[0059] (3) insulation

[0060] Then keep warm at this temperature for 3h;

[0061] (4) Recovery of thionyl chloride

[0062] The reaction solution was transferred to a rectification device, and excess thionyl chloride was recovered by rectification under reduced pressure, and the recovered thionyl chloride content was 99.3%, and the recovery rate was 93.6%;

[0063] (5) Vacuum distillation

[0064] Continue vacuum distillation to obtain 4,6-dichloropyrimidine product with a content of 99.6% and a yield of 95.6%;

[0065] (6) Recovery of N,N-dimethylaniline

[0066] The rem...

Embodiment 3

[0068] (1) Feeding

[0069] Put 1 mole of 4,6-dihydroxypyrimidine and 8 moles of thionyl chloride into the reaction flask;

[0070] (2) Add N,N-dimethylaniline dropwise

[0071] Weigh 2.3 moles of N,N-dimethylaniline into the constant pressure dropping funnel for later use, turn on the stirring and heating mantle, raise the temperature to 60°C, and slowly add N,N-dimethylaniline dropwise for 3 hours;

[0072] (3) insulation

[0073] Then keep warm at this temperature for 4h;

[0074] (4) Recovery of thionyl chloride

[0075] The reaction solution was transferred to a rectification device, and excess thionyl chloride was recovered by rectification under reduced pressure, and the recovered thionyl chloride content was 99.2%, and the recovery rate was 92%;

[0076] (5) Vacuum distillation

[0077] Continue vacuum distillation to obtain 4,6-dichloropyrimidine product with a content of 99.3% and a yield of 94.5%;

[0078] (6) Recovery of N,N-dimethylaniline

[0079] The rema...

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PUM

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Abstract

The invention provides a synthesis process of 4,6-dichloropyrimidine. The synthesis process takes thionyl chloride as a chlorinating agent and solvent for reactions, 4,6-dihydroxypyrimidine as a raw material, and N, N-dimethyl aniline as a catalyst. Compared with the prior art, thionyl chloride is used as a chlorinating agent and a solvent for reactions during the preparation process of 4,6-dichloropyrimidine, and no other organic solvent is introduced, so that the influence of other solvents on the product is reduced. According to the invention, less wastewater is generated; the finally generated wastewater is mainly composed of a salt solution of sodium sulfite and sodium chloride; excessive thionyl chloride is recycled in a rectification mode, the part of generated wastewater is only limited to the consumed thionyl chloride part, about 6-7 kg of wastewater is generated from 1 kg of 4,6-dichloropyrimidine product, and solid salt is obtained through concentration and crystallization in wastewater after treatment.

Description

technical field [0001] The invention relates to the synthesis of a drug intermediate raw material, in particular to a synthesis process of 4,6-dichloropyrimidine, which belongs to the field of organic chemistry. Background technique [0002] 4,6-Dichloropyrimidine is a heterocyclic compound. Due to its special structure, it is widely used in medicine and pesticides. It is an important intermediate for the synthesis of sulfonamides and the fungicide azoxystrobin. Due to the large market demand, the research on 4,6-dichloropyrimidine should be increased to improve the industrial production level. [0003] At present, there are mainly three existing techniques for synthesizing 4,6-dichloropyrimidine, which are respectively one: 4,6-dihydroxypyrimidine reacts with phosphorus oxychloride under the action of an organic base to obtain 4,6-dichloropyrimidine; : 4,6-dihydroxypyrimidine reacts with phosphorus oxychloride, phosphorus trichloride and chlorine to obtain 4,6-dichloropyri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D239/30
CPCC07B2200/13C07D239/30
Inventor 张新伟陈志东窦荣坦杨文涛王美杰王帅
Owner 潍坊滨海石油化工有限公司
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