反应详情

温度

-90 °C

3.09 g of TMEDA were dissolved in 30 ml of THF (anhydrous) and added dropwise at −90° C. to 20.5 ml of a 1.3M solution of sec-butyllithium in cyclohexane. A solution of 3.0 g of 4-pentafluorosulfanylbenzoic acid in 20 ml of THF (anhydrous) was then added dropwise at −90° C. After stirring at −90° C. for one hour, a solution of 5.15 g of methyl iodide in 20 ml of THF (anhydrous) was added dropwise. The temperature was kept at −80° C. during this. After stirring at −78° C. for 20 minutes, 100 ml of water were injected, a dilute aqueous HCl solution was used to adjust to pH=1, and the mixture was extracted 3 times with 100 ml of MTB each time. After drying over MgSO4, the solvent was removed in vacuo. The residue was initially chromatographed on silica gel with DIP/2% HOAc, and 1.60 g of a mixture of 4-pentafluorosulfanylbenzoic acid and 4-pentafluorosulfanyl-2-methylbenzoic acid were obtained. This mixture was rechromatographed under the following conditions:

1. customwas kept at −80° C.
2. stirringAfter stirring at −78° C. for 20 minutes
3. extractionthe mixture was extracted 3 times with 100 ml of MTB each time
4. dry with materialAfter drying over MgSO4
5. customthe solvent was removed in vacuo
6. customThe residue was initially chromatographed on silica gel with DIP/2% HOAc, and 1.60 g of a mixture of 4-pentafluorosulfanylbenzoic acid