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A kind of preparation method of methyl 2,2-difluoropiperate

A technology of methyl difluoropiperate and difluoropiperonyl fluoride is applied in 2 fields, can solve the problems of high cost, low total reaction yield, long steps and the like, and achieves the advantages of short synthesis route, reduced environmental pollution and complete reaction. Effect

Active Publication Date: 2017-03-08
QUZHOU CHEMSPEC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The cost of this method is high, and the raw materials used need to be prepared through chlorination, fluorination and bromination, the steps are long, and the total reaction yield is low

Method used

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  • A kind of preparation method of methyl 2,2-difluoropiperate
  • A kind of preparation method of methyl 2,2-difluoropiperate
  • A kind of preparation method of methyl 2,2-difluoropiperate

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preparation example Construction

[0033] The invention provides a kind of preparation method of methyl 2,2-difluoropiperate, comprising the steps of:

[0034] 1) Chlorination reaction: use piperonal as raw material, react with chlorine gas under the action of initiator or photoinitiation to prepare 2,2-dichloropiperoyl chloride, the reaction equation is as follows:

[0035]

[0036] Preferably, the specific method of the chlorination reaction is: when using an initiator to initiate the chlorination reaction, chlorine gas, piperonal dissolved in a reaction solvent, and the initiator are added to the reaction vessel simultaneously; when using light to initiate the chlorination reaction, Chlorine and piperonal dissolved in the reaction solvent are added to the reaction vessel simultaneously, and the reaction system is illuminated; the ratio of the speed of addition of chlorine to the speed of addition of piperonal in the reaction solvent is preferably 2-10 times the molar amount, more preferably 2-5:1, most pr...

Embodiment 1

[0062] 2, Preparation of 2-dichloropiperoyl chloride

[0063] After 300g piperonal, 0.3g azobisisobutyronitrile are mixed and dissolved with 600g p-chlorobenzotrifluoride, they are added dropwise in the reactor, while feeding chlorine (total amount 426g) at a speed of 71g / hour, and keep The internal temperature is 120-140°C. The piperonal solution was added dropwise in about 6 hours, and the reaction ended. Degassing under reduced pressure, then removing p-chlorotrifluorotoluene under reduced pressure, and then distilling under reduced pressure to collect fractions at 134-136°C / 1.4kPa to obtain 479g of 2,2-dichloropiperonyl chloride. The yield of the chlorination reaction was was 94.4%.

Embodiment 2

[0065] Preparation of 2,2-difluoropiperonyl fluoride

[0066] Put 479g of 2,2-dichloropiperonyl chloride into the polytetrafluoro reactor, raise the temperature inside the reactor to 40°C, and feed 120g of hydrogen fluoride under stirring, and then stir at 50-70°C for half an hour to react Finish. Measured by GC-MS method, the reaction product is 2,2-difluoropiperoyl fluoride. This reaction solution was directly used for the next reaction.

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Abstract

The invention relates to the field of organic synthesis, in particular to a preparation method of 2,2-difluoro methyl piperate. The preparation method of the 2,2-difluoro methyl piperate includes the following steps that 2,2- difluoro piperyl fluorine (II) and methanol are reacted, 2,2- difluoro methyl piperate (III) is obtained through esterification reaction, and please see the reaction formula in the specifications. The preparation method of 2,2-difluoro methyl piperate has the advantages that the synthesis route is short, the process is easy to control, reaction is complete, the yield is high, and prepared target products are high in purity, are stable in quality and completely meet the use requirements as a pesticide or medical intermediate; in addition, raw materials and reagents used in the method are cheap, the amount of solvents used in each step of reaction is small, a little waste liquid is generated, the cost is reduced, environmental pollution is reduced, and the 2,2-difluoro methyl piperate is quite convenient to produce in a large scale in a commercialization mode.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a preparation method of methyl 2,2-difluoropiperate. Background technique [0002] Methyl 2,2-difluoropiperate is an increasingly versatile intermediate that is commonly used in the synthesis of pharmaceutical compounds, pesticide compounds and electronic chemicals. In the prior art, 5-bromo-2,2-difluoropiperonyl and carbon monoxide are reacted under high pressure under the catalysis of tetrakistriphenylphosphorous palladium to prepare corresponding methyl 2,2-difluoropiperonate (WO2005075435 ). The cost of this method is relatively high, and the raw materials used need to be prepared through chlorination, fluorination and bromination, the steps are long, and the total reaction yield is low. Contents of the invention [0003] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a method for preparing methyl 2,2-difluo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D317/46
CPCC07D317/68
Inventor 蔡国荣刘俊俞佳麟龚雪莲
Owner QUZHOU CHEMSPEC CORP
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