Reaction #411184

Reaction equation

sulphuric acid

benzothiophene

potassium chloride

→

title compound

Benzo[b]thiophene-3-sulfonic acid potassium salt

Solvents

acetic anhydride

Conditions

Workup

1. 1
   Othergiving a brown viscous oil, which
2. 2
   workup.WAITwas left
3. 3
   workup.STIRRINGto stir for 50 mins under nitrogen
4. 4
   workup.ADDITIONThe mixture was then diluted with ice
5. 5
   Otherto give 20 ml
6. 6
   Extractionextracted with ether (2×10 ml)
7. 7
   Concentrationthe aqueous phase concentrated in vacuo
8. 8
   Otherto give 5 ml
9. 9
   Temperaturecooled
10. 10
    Filtrationfiltered

Procedure

Concentrated sulphuric acid (0.43 ml) was added to a cooled, stirred mixture of benzothiophene (1 g) in acetic anhydride (0.93 ml), giving a brown viscous oil, which was left to stir for 50 mins under nitrogen. The mixture was then diluted with ice to give 20 ml, extracted with ether (2×10 ml) and the aqueous phase concentrated in vacuo to give 5 ml. This was then treated with a hot saturated solution of potassium chloride (2 g), cooled and filtered to give the title compound as a pale brown solid (3.935 g).

Source