Reaction #684996

Reaction equation

water

acetone

2-(2-(1-benzothiophene-6-yl)ethoxy)-1-(3-hydroxy-1-pyrrolidinyl)-1-ethanone

hydrochloric acid

→

yellow oil

1-(2-(2-(1-benzothiophene-6-yl)ethoxy)ethyl)-3-pyrrolidinol

Solvents

tetrahydrofuran

ethyl acetate

tetrahydrofuran

Conditions

Workup

1. 1
   workup.ADDITIONwas added dropwise to the obtained solution
2. 2
   Temperaturewhile cooling on ice
3. 3
   workup.STIRRINGthe obtained mixture was then stirred for 30 minutes
4. 4
   Temperaturethe obtained mixture was heated
5. 5
   Temperatureto reflux for 2 hours
6. 6
   TemperatureAfter the reaction mixture was cooled
7. 7
   Othera water layer was separated
8. 8
   workup.ADDITIONThereafter, ethyl acetate was added to the water layer
9. 9
   workup.ADDITIONThe pH of the obtained mixture was adjusted to pH 9.5 by addition of a 2 mol/l aqueous sodium hydroxide solution
10. 10
    Otherfollowed by separation of an organic layer
11. 11
    WashThe organic layer was successively washed with water
12. 12
    Dryinga saturated saline solution, and then dried over anhydrous magnesium sulfate
13. 13
    workup.DISTILLATIONThereafter, the solvent was distilled away under a reduced pressure
14. 14
    OtherThe residue was purified by column chromatography (eluent; chloroform:methanol=30:1 to 20:1)

Procedure

The above 2-(2-(1-benzothiophene-6-yl)ethoxy)-1-(3-hydroxy-1-pyrrolidinyl)-1-ethanone was dissolved in 7.4 ml of tetrahydrofuran. Thereafter, 7.4 ml of a tetrahydrofuran solution containing a 1 mol/l borane-tetrahydrofuran complex was added dropwise to the obtained solution while cooling on ice, and the obtained mixture was then stirred at a room temperature for 17 hours. Thereafter, 10 ml of acetone was added to the reaction mixture, and the obtained mixture was then stirred for 30 minutes. Thereafter, 1.5 ml of 6 mol/l hydrochloric acid was added thereto, and the obtained mixture was heated to reflux for 2 hours. After the reaction mixture was cooled, water and ethyl acetate were added thereto, and a water layer was separated. Thereafter, ethyl acetate was added to the water layer. The pH of the obtained mixture was adjusted to pH 9.5 by addition of a 2 mol/l aqueous sodium hydroxide solution, followed by separation of an organic layer. The organic layer was successively washed with water and a saturated saline solution, and then dried over anhydrous magnesium sulfate. Thereafter, the solvent was distilled away under a reduced pressure. The residue was purified by column chromatography (eluent; chloroform:methanol=30:1 to 20:1), so as to obtain 0.53 g of a yellow oil product, 1-(2-(2-(1-benzothiophene-6-yl)ethoxy)ethyl)-3-pyrrolidinol.

Source