Sodium Carbonate → 3-Fluoro-4-(methylsulfonyl)phenylhydrazine

Temperature

65 °C

To a stirred suspension of 3-fluoro-4-(methylsulfonyl)aniline (8.1 g, 42.9 mmol) in 20% aqueous HCl (27 mL) was added dropwise a solution of sodium nitrite (3 g, 43.5 mmol) in water (20 mL) at 0° C. After stirring for 1 hour, the resulting suspension was added to a solution of sodium sulfite (13.5 g, 110 mmol) in water (60 mL) and 20% aqueous NaOH (3 mL) at 0-5° C. Then the mixture was heated at 60-70° C. for 2 hours, and conc. HCl (3.5 mL) was added. The resulting mixture was heated for further 5 hours at 60° C. After cooling down to room temperature, the mixture was made basic by Na2CO3. The whole was extracted with THF (150 mL×3), the combined organic layer washed with brine (100 mL), dried over MgSO4, and concentrated in vacuo. The resulting solid was recrystallized from EtOH to give 3-fluoro-4-(methylsulfonyl)phenylhydrazine (5 g, 57% yield).

1. temperatureThe resulting mixture was heated for further 5 hours at 60° C
2. temperatureAfter cooling down to room temperature
3. extractionThe whole was extracted with THF (150 mL×3)
4. washthe combined organic layer washed with brine (100 mL)
5. dry with materialdried over MgSO4
6. concentrationconcentrated in vacuo
7. customThe resulting solid was recrystallized from EtOH

ORD record

ord-d1554f3555d648bb9e49a8de5a708d3a

Source dataset

uspto-grants-2005_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06949536B2