Method for preparing ethyl 4,4-difluoroacetoacetate

A technology of ethyl difluoroacetoacetate and ethyl difluoroacetate is applied in the field of preparation of ethyl 4,4-difluoroacetoacetate, and can solve the problems of low safety factor, large amount of three wastes, large waste water, etc. The effect of high selectivity, improved selectivity and simple process

Inactive Publication Date: 2018-06-29
ZHEJIANG LANTIAN ENVIRONMENTAL PROTECTION HI TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because this method uses sodium hydride as a catalyst, a large amount of hydrogen will be generated, so the safety factor is low, and after the reaction, the organic matter will be extracted by washing and extraction operations, which will generate a large amount of waste water and a large amount of three wastes.

Method used

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  • Method for preparing ethyl 4,4-difluoroacetoacetate
  • Method for preparing ethyl 4,4-difluoroacetoacetate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Add 200mL of absolute ethanol to the reactor at 25°C, then add 510g (1.5mol) of 20% sodium ethoxide ethanol solution, and cool the reaction solution to 5-10°C. Then start to drop a mixture of 105.6g (1.2mol) ethyl acetate and 124g (1.0mol) ethyl difluoroacetate, and control the temperature at 10-20°C. After the addition, the temperature was raised to 60°C to react for 2 hours, and then the reaction solution was cooled to 10-15°C. Add 166.6 g (1.7 mol) of concentrated sulfuric acid dropwise to the reaction solution, control the temperature at 20-30° C., and react at 30° C. for 2.5 hours after dropping, to obtain a turbid solution containing sodium sulfate precipitate.

[0051] The sodium sulfate precipitate was removed by filtration, and the filter cake was washed with ethyl acetate, and the obtained filtrate was subjected to rectification under reduced pressure to obtain 149.7g ethyl difluoroacetoacetate, and the yield was 90.2% (in terms of ethyl difluoroacetate), The...

Embodiment 2

[0053] At 25°C, 100 mL of cyclohexane was added to the reactor, and then 374 g (0.55 mol) of 10% sodium ethoxide ethanol solution was added, and the reaction solution was cooled to 5-10°C. Then start to drop a mixture of 57.2g (0.65mol) ethyl acetate and 62g (0.5mol) ethyl difluoroacetate, and control the temperature at 15-20°C. After the addition, the temperature was raised to 50°C to react for 3 hours, and then the reaction solution was cooled to 10-15°C. Add 59.2g (0.6mol) 37% concentrated hydrochloric acid dropwise to the reaction solution, control the temperature at 20-30°C, and react at 40°C for 1.5 hours after the dropwise completion to obtain a turbid solution containing sodium chloride precipitate.

[0054] The sodium chloride precipitate was removed by filtration, the filter cake was washed with ethyl acetate, and the obtained filtrate was subjected to rectification under reduced pressure to obtain 75.2 g of ethyl difluoroacetoacetate, with a yield of 90.6% (in terms...

Embodiment 3

[0056] At 25°C, 100 mL of tetrahydrofuran will be added to the reactor, and then 385.3 g (0.85 mol) of 15% sodium ethoxide ethanol solution will be added, and the reaction liquid will be cooled to 5-10°C. Then start to drop a mixture of 70.4g (0.8mol) ethyl acetate and 86.8g (0.7mol) ethyl difluoroacetate, and control the temperature at 10-20°C. After the addition, the temperature was raised to 40°C to react for 4 hours, and then the reaction solution was cooled to 10-15°C. Add 54 g (0.9 mol) of acetic acid dropwise to the reaction solution, control the temperature at 20-30° C., and react at 35° C. for 2.0 hours after the drop is completed, to obtain a turbid solution containing sodium acetate precipitate.

[0057] The sodium acetate precipitate was removed by filtration, and the filter cake was washed with ethyl acetate, and the obtained filtrate was rectified under reduced pressure to obtain 106.1 g of ethyl difluoroacetoacetate, with a yield of 91.3% (in terms of ethyl difl...

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Abstract

The invention discloses a method for preparing ethyl 4,4-difluoroacetoacetate. The method comprises the following step: by taking ethyl difluoroacetate and ethyl acetate as raw materials, and an ethanol solution of sodium ethoxide as a catalyst, in the presence of an organic solvent, carrying out a Claisen condensation reaction, thereby obtaining the ethyl 4,4-difluoroacetoacetate. The method disclosed by the invention has the characteristics of being gentle in reaction condition, high in security, good in reaction selectivity, easy in product separation and purification, applicable to industrial production, and the like.

Description

technical field [0001] The invention relates to a preparation method of ethyl 4,4-difluoroacetoacetate. Background technique [0002] In recent years, the application of difluoromethyl compounds in the creation of medicines and pesticides has attracted widespread attention. Compared with trifluoromethyl, difluoromethyl can significantly enhance the physiological activity of organic molecular compounds. In many biological organic molecules Play an important role. The main reason is that in addition to the simulation effect and hindering effect of the fluorine atom, the hydrogen atom in the difluoromethyl group can also be used as a hydrogen bond donor to further improve the efficacy of the drug. In contrast, fluoride ion is a good leaving group, and fluorine atom in organic molecules can often be used as a leaving group to achieve the interaction between enzymes and fluorine-containing substrates in vivo, thereby producing obvious physiological effects. [0003] Ethyl 4,4-d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C67/313C07C69/716
CPCC07C67/313C07C67/343C07C69/716C07C69/732
Inventor 李华陈伟徐卫国蒋强杨汪松
Owner ZHEJIANG LANTIAN ENVIRONMENTAL PROTECTION HI TECH
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