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CN-121990957-A - Preparation process of trifluoroethyl diphenyl sulfonium salt

CN121990957ACN 121990957 ACN121990957 ACN 121990957ACN-121990957-A

Abstract

The invention relates to the technical field of compound preparation, in particular to a preparation process of 2, 2-trifluoroethyl diphenyl sulfonium triflate. The method comprises the following steps of reacting 2, 2-trifluoroethanol, formic acid and acetic anhydride, rectifying reaction liquid, collecting target fractions to obtain 2, 2-trifluoroethyl formate, reacting 2, 2-trifluoroethyl formate, diphenyl sulfide and trifluoromethanesulfonic acid, cooling the reaction liquid, separating out solids, washing with an organic solvent to obtain 2, 2-trifluoroethyl diphenyl sulfonium trifluoromethanesulfonate, wherein the purity can reach 99.7%, and the total reaction yield can reach 78.93%. The preparation process provided by the invention has the advantages of low-cost and easily-obtained raw materials, simple and convenient operation, high reaction yield, mild reaction conditions, high safety, simple post-reaction treatment and suitability for industrial large-scale production.

Inventors

  • XU BENQUAN
  • WU LINYAN
  • CHEN GUOQING

Assignees

  • 南通华祥医药科技有限公司

Dates

Publication Date
20260508
Application Date
20260326

Claims (8)

  1. 1. A process for preparing 2, 2-trifluoroethyl diphenyl sulfonium triflate, which is characterized by comprising the following steps: step one, 2-trifluoroethanol, formic acid and acetic anhydride react, the reaction liquid is rectified, and target fractions are collected to obtain 2, 2-trifluoroethyl formate; ; step two, 2-trifluoroethyl formate, diphenyl sulfide and trifluoromethanesulfonic acid react, the reaction liquid is cooled, solid is separated out, and the 2, 2-trifluoroethyl diphenyl sulfonium trifluoromethanesulfonate is obtained by washing with an organic solvent, 。
  2. 2. The preparation process of 2, 2-trifluoroethyl diphenyl sulfonium triflate according to claim 1, wherein the molar ratio of 2, 2-trifluoroethanol to formic acid to acetic anhydride is 1:1-1.5:1-2 in the first step, and the molar ratio of 2, 2-trifluoroethyl formate to diphenyl sulfide to triflic acid is 1:2-4:1-1.5 in the second step.
  3. 3. The process for preparing 2, 2-trifluoroethyl diphenyl sulfonium triflate according to claim 1, wherein in the first step, formic acid and acetic anhydride are sequentially added into a reaction container, 2-trifluoroethanol is dropwise added, and 2, 2-trifluoroethyl formate is obtained through reaction.
  4. 4. The process for preparing 2, 2-trifluoroethyl diphenyl sulfonium triflate according to claim 3, wherein the system temperature is controlled to be 35-40 ℃ when 2, 2-trifluoroethanol is added dropwise, the reaction temperature is 35-45 ℃, and the reaction time is 1.5-2.5 h.
  5. 5. The process for producing 2, 2-trifluoroethyldiphenyl sulfonium triflate according to claim 1, wherein in the first step, a rectification column filled with a glass spring filler is used, the length of the rectification column is 25-35 cm, and the target fraction is a fraction collected at a top temperature of 58-62 ℃.
  6. 6. The process for preparing 2, 2-trifluoroethyl diphenyl sulfonium triflate according to claim 1, wherein in the second step, diphenyl sulfide and trifluoromethanesulfonic acid are sequentially added into a reaction container, 2-trifluoroethyl formate is dropwise added, and the 2, 2-trifluoroethyl diphenyl sulfonium triflate is obtained through reaction.
  7. 7. The process for preparing 2, 2-trifluoroethyl diphenyl sulfonium triflate according to claim 6, wherein the system temperature is controlled to be 50-55 ℃ and the reaction time is controlled to be 1.5-2.5 h when 2, 2-trifluoroethyl formate is added dropwise.
  8. 8. The process for preparing 2, 2-trifluoroethyl diphenyl sulfonium triflate according to claim 1, wherein the cooling temperature is-5 ℃, the solid precipitation time is 0.5-2 h, and the organic solvent is one of petroleum ether, n-hexane or n-heptane.

Description

Preparation process of trifluoroethyl diphenyl sulfonium salt Technical Field The invention relates to the technical field of compound preparation, relates to a preparation process of trifluoroethyl diphenyl sulfonium salt, and in particular relates to a preparation process of 2, 2-trifluoroethyl diphenyl sulfonium trifluoro methane sulfonate. Background 2, 2-Trifluoroethyldiphenylsulfonium triflate (CAS: 135654-49-8) is an important fluorinating agent and has extremely wide application due to its excellent stability, availability and ease of handling. It is used in a number of innovative trifluoroalkylation reactions including photooxidation-reduction trifluoroethylation, iron catalyzed intercalation, cyclopropanation, johnson-Corey-Chaykovsky reactions, and [4+1] cycloaddition reactions. The 2, 2-trifluoro ethyl diphenyl sulfonium trifluoro methane sulfonate is used for synthesizing trifluoro ethyl compounds and various trifluoro methylation cyclopropane, epoxide, aziridine, pyrrole derivatives and pyrazoline, and has high diastereoselectivity. However, only 2 cases of reports about the preparation method of 2, 2-trifluoro ethyl diphenyl sulfonium trifluoro methane sulfonate exist at present, and the preparation method is complex and is not suitable for large-scale preparation. Umemoto in 1991, the preparation （Synthesis of 2,2,2-Trifluoroethylated Onium Salts of Nitrogen, Sulfur, and Phosphorus with (2,2,2-Trifluoroethyl)phenyliodonium Triflate）, of 2, 2-trifluoroethyldiphenyl sulfonium triflate was reported for the first time as follows: 。 The preparation method has the advantages that dichloromethane is used as a solvent, the reaction is carried out at room temperature, and the reaction condition is mild. However, the preparation of 2, 2-trifluoroethyl (phenyl) iodonium triflate is complicated, the reaction conditions are severe, and the preparation cannot be performed in a large amount. The process for preparing 2, 2-trifluoroethyldiphenyl sulfonium triflate was optimized by the group of the problem of Sho Ji Chang (CN 105523873A), and the specific reaction equation is as follows: 。 The method takes 2, 2-trifluoroethyl trifluoro methane sulfonate and diphenyl sulfide as raw materials, the raw materials are mixed and then heated to 150 ℃ in a closed reactor for reaction 24h, white solid is separated out after the reaction liquid is cooled to room temperature, and the product can be obtained through suction filtration, and the yield is 80%. However, this process has two significant disadvantages, namely 1) the relatively high price of the starting material 2, 2-trifluoroethyl trifluoromethane sulfonate, and 2) the boiling point of the starting material 2, 2-trifluoroethyl trifluoromethane sulfonate is 89 to 91℃and the reaction temperature is 150℃so that the reaction needs to be carried out in a closed reactor, resulting in a high pressure in the closed reactor and a relatively dangerous condition. 2, 2-trifluoroethyl trifluoromethane sulfonate is easily decomposed at high temperature, and thus it is difficult to perform mass production by this method. Disclosure of Invention The invention aims to overcome the defects existing in the prior art and provide a preparation process of 2, 2-trifluoroethyl diphenyl sulfonium triflate, the method has the advantages of cheap and easily obtained raw materials, simple and convenient operation, high yield, mild reaction conditions and high safety, and is suitable for industrial mass production. The invention provides a preparation process of 2, 2-trifluoro ethyl diphenyl sulfonium trifluoro methane sulfonate, which comprises the following steps: step one, 2-trifluoroethanol, formic acid and acetic anhydride react, the reaction liquid is rectified, target fractions are collected, 2-trifluoroethyl formate is obtained, ; Step two, 2-trifluoroethyl formate, diphenyl sulfide and trifluoromethanesulfonic acid react, the reaction liquid is cooled, solid is separated out, and the 2, 2-trifluoroethyl diphenyl sulfonium trifluoromethanesulfonate is obtained by washing with an organic solvent, 。 Further, the molar ratio of the 2, 2-trifluoroethanol to the formic acid to the acetic anhydride is 1:1-1.5:1-2, and the molar ratio of the 2, 2-trifluoroethyl formate to the diphenyl sulfide to the trifluoromethanesulfonic acid is 1:2-4:1-1.5. Further, in the first step, formic acid and acetic anhydride are sequentially added into a reaction container, 2-trifluoroethanol is dropwise added for reaction to obtain 2, 2-trifluoroethyl formate, when 2, 2-trifluoroethanol is dropwise added, the system temperature is controlled to be 35-40 ℃, the reaction temperature is 35-45 ℃, and the reaction time is 1.5-2.5 hours. Further, in the first step, a rectifying column filled with glass spring filler is used, the length of the rectifying column is 25-35 cm, and the target fraction is collected when the top temperature is 58-62 ℃. Further, in the second step, diphenyl sulfide and trifluoromethane