反应详情

Sulfanilic acid (0.767 g, 4.43 mmol) was dissolved in hot mixture of 20 mL of water and 10 mL of conc. HCl. The solution was cooled in ice/NaCl bath to 0° C. giving a suspension of HCl salt. The solution of sodium nitrite (0.367 g, 5.32 mmol in 5 mL of water) was added dropwise to the suspension of ammonium salt, maintaining the temperature below +5° C. All solid dissolved and the resulting solution was stirred for 20 min. After that white precipitate formed again and the resulting suspension was added dropwise to the mixture of 2,6-difluorophenol (0.576 g, 4.43 mmol) in 10 mL of dioxane and KOH (10 g) in 15 mL of water, cooled in ice/water bath. The reaction mixture was stirred for 30 min in ice/water bath and then extracted with ethyl acetate (3×30 mL). The aqueous solution was acidified with 10% HCl to pH 2-3 and the formed yellow precipitate was collected, washed with water and dried in vacuum to give phenol 2 as a yellow powder (1.1 g, 79%).

1. customgiving
2. temperaturemaintaining the temperature below +5° C
3. dissolutionAll solid dissolved
4. customAfter that white precipitate formed again
5. extractionextracted with ethyl acetate (3×30 mL)
6. customthe formed yellow precipitate was collected
7. washwashed with water
8. customdried in vacuum