A kind of preparation method of 2,2-difluoropiperic acid methyl ester

Abstract

The invention discloses a preparation method of methyl 2,2-difluorobenzo[d][1,3]dioxole-5-carboxylate. The method comprises the steps of performing cyanation reaction to 5-bromo-2,2-difluoro-1,3-benzodioxole and cuprous cyanide, then performing hydrolysis to form acid, and then performing esterification to obtain 2,2-difluorobenzo[d][1,3]dioxole-5-carboxylate. In the preparation method disclosed by the invention, by using 5-bromo-2,2-difluoro-1,3-benzodioxole as a start raw material, performing cyanation by using low-toxicity cuprous cyanide, then performing hydrolysis to form acid and performing methanol reaction esterification to obtain the product, the process flow of the method is simple and the reaction process is easy to control. In the reaction process, the purification of the intermediate product produced in each step does not need a complex purification process, the purification process is simple, the purification yield is high, the entire process flow is simple and high-efficiency, the product yield is high, the cost of the entire flow is low and the preparation method is very suitable for large-scale industrial production.

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 important intermediate, which is often used in the synthesis of pharmaceutical compounds, pesticide compounds and electronic chemicals. Its methyl ester is a lively substituent group with strong extensibility. [0003] There are two methods for the synthesis of methyl 2,2-difluoropiperate commonly used at present: [0004] Method 1: 3,4-dihydroxynitrobenzene is used as the starting material, first synthesize 5-nitro-2,2-difluoropiperone ring, then reduce and diazotize the bromine, and use carbon dioxide to form an acid under high pressure, and then Ester into 2,2-methyl difluoropiperate. The raw materials of this method are rare, and the operation is cumbersome, which is greatly limited in industrialized large-scale production. [0005] Method 2: Use 5-bromo-2,2...

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Problems solved by technology

[0008] Therefore, the technical problem to be solved in the present invention is to overcome the toxic gas involved in the preparation process of methyl 2,2-difluoropiperate in the prior art, the reaction process is not easy to control, the environment is easy to pollute, and the purification process is more loaded down with trivial details, thereby providing A method for preparing methyl 2,2-difluoropiperate with low toxicity to the environment, simple purification in the preparation process, and simple process flow

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