Reaction #1532

Reaction equation

ammonium chloride

n-butyl lithium

N-t-butyl-3-bromo-2-thiophenesulfonamide

ethyl fluoroacetate

→

pure title compound

Yield 72.0%

N-t-butyl-3-(fluoroacetyl)-2-thiophenesulfonamide

Yield 72.0%

Solvents

ethylacetate

tetrahydrofuran

Conditions

Workup

1. 1
   Temperaturethe temperature of the mixture was raised slowly to -20° C.
2. 2
   Temperatureagain cooled to -78° C
3. 3
   TemperatureThe temperature of the mixture was raised again slowly to -20° C.
4. 4
   Otherto separate the organic layer
5. 5
   DryingThe extracted organic layer was dried over anhydrous magnesium sulfate
6. 6
   Concentrationconcentrated

Procedure

2.98 g (0.0mole) of N-t-butyl-3-bromo-2-thiophenesulfonamide was dissolved in 50mi of dry tetrahydrofuran and the mixture was cooled to -78° C. under nitrogen gas. To the reaction solution was slowly added dropwise 8.4 ml of n-butyl lithium (2.5N) and then the temperature of the mixture was raised slowly to -20° C. and again cooled to -78° C. 1.2 g (0.011 mole) of ethyl fluoroacetate was added slowly to the reaction mixture. The temperature of the mixture was raised again slowly to -20° C. and then the mixture was stirred for 10 minutes. To the reaction mixture was added 100 ml of 5% aqueous ammonium chloride solution, and then added 100 ml of ethylacetate to separate the organic layer. The extracted organic layer was dried over anhydrous magnesium sulfate and concentrated. The residue was subjeced to column chromatography on silica gel to obtain 2.0 g (Yield: 72%) of the pure title compound as a liquid.

Source