Reaction #1269817

Reaction equation

benzo[b]thiophene-2-sulfonyl chloride

nitric acid

→

product

Mono nitro-benzo[b]thiophene-2-sulfonyl chloride

Solvents

dichloromethane

Conditions

Workup

1. 1
   Temperaturethe resulting mixture was refluxed overnight
2. 2
   OtherThe organic layer was separated
3. 3
   Extractionthe aqueous layer was extracted by 220 mL 2 dichloromethane
4. 4
   Dryingdried over MgSO4
5. 5
   OtherSolvent was then removed by rotary evaporator
6. 6
   OtherThe crude product was purified by flash column chromatography with an eluent of hexane

Procedure

To a solution of benzo[b]thiophene-2-sulfonyl chloride (1.165 g, 5 mmol) in 25 mL of dichloromethane was added 3.6 mL of concentrated nitric acid (≧22.05 mol/L) dropwise, the resulting mixture was refluxed overnight and cooled to room temperature before it was poured into 20 gram of crushed ice. The organic layer was separated and the aqueous layer was extracted by 220 mL 2 dichloromethane. The organic layers were combined and dried over MgSO4. Solvent was then removed by rotary evaporator. The crude product was purified by flash column chromatography with an eluent of hexane, followed by a gradient eluent of hexane/ethyl acetate (6/1-3/1) to afford 0.58 g of product (mixture of 65% of 4-nitro-benzo[b]thiophene-2-sulfonyl chloride and 35% of 7-nitro-benzo[b]thiophene-2-sulfonyl chloride).

Source