Reaction #7558

Reaction equation

water

3-[2-(1-benzothiophen-5-yl)ethoxy]-1-propanol

triphenylphosphine

carbon tetrabromide

→

5-[2-(3-bromopropoxy)ethyl]-1-benzothiophene

Yield 76.2%

Solvents

methylene chloride

methylene chloride

Conditions

Workup

1. 1
   workup.ADDITIONwas added to the solution
2. 2
   Temperatureunder ice-cooling
3. 3
   Otherthe organic layer was separated
4. 4
   WashThe organic layer was washed with a saturated aqueous sodium hydrogencarbonate solution
5. 5
   Dryinga saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate
6. 6
   workup.DISTILLATIONdistilled under reduced pressure
7. 7
   Otherto remove the solvent
8. 8
   workup.ADDITIONDiethyl ether was added to the residue
9. 9
   Filtrationthe insoluble materials were filtered off
10. 10
    workup.DISTILLATIONafter which the solvent was distilled off under reduced pressure
11. 11
    OtherThe residue was purified by a column chromatography (eluent; hexane:ethyl acetate=20:1 to 10:1)

Procedure

In 40 mL of methylene chloride was dissolved 2.00 g of 3-[2-(1-benzothiophen-5-yl)ethoxy]-1-propanol, and 5.55 g of triphenylphosphine was added to the solution, after which a solution of 8.42 g of carbon tetrabromide in 10 mL of methylene chloride was added dropwise thereto under ice-cooling and the resulting mixture was stirred at room temperature for 20 minutes. To the reaction mixture was added 20 mL of water, and the organic layer was separated. The organic layer was washed with a saturated aqueous sodium hydrogencarbonate solution and then a saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, and then distilled under reduced pressure to remove the solvent. Diethyl ether was added to the residue and the insoluble materials were filtered off, after which the solvent was distilled off under reduced pressure. The residue was purified by a column chromatography (eluent; hexane:ethyl acetate=20:1 to 10:1) to obtain 1.93 g of 5-[2-(3-bromopropoxy)ethyl]-1-benzothiophene as a colorless oil.

Source