Reaction #2446064

Reaction equation

Toluene

p-toluenesulfonic acid monohydrate

3-butyl-1-(4-ethoxy-2,3-difluorophenyl)cyclopentanol

→

1-(3-butylcyclopent-1-enyl)-4-ethoxy-2,3-difluorobenzene

Yield 91.2%

Solvents

water

Conditions

Workup

1. 1
   Otherobtained in the second step, in a reaction vessel
2. 2
   Otherequipped with a Dean-Stark apparatus under an atmosphere of nitrogen
3. 3
   TemperatureThe mixture was refluxed for 30 minutes
4. 4
   Otherwas removed with a Dean-Stark apparatus
5. 5
   Washwas washed with water
6. 6
   DryingThe solution was dried over anhydrous magnesium sulfate
7. 7
   workup.DISTILLATIONthe solvent was distilled off under reduced pressure
8. 8
   OtherThe residue was purified by silica gel chromatography (eluent: ethyl acetate/n-heptane= 1/9 by volume)

Procedure

Toluene (50 ml) and p-toluenesulfonic acid monohydrate (0.14 g) were added to 3-butyl-1-(4-ethoxy-2,3-difluorophenyl)cyclopentanol (2.8 g) obtained in the second step, in a reaction vessel equipped with a Dean-Stark apparatus under an atmosphere of nitrogen. The mixture was refluxed for 30 minutes, while forming water was removed with a Dean-Stark apparatus. The reaction solution was cooled to room temperature and was washed with water. The solution was dried over anhydrous magnesium sulfate and the solvent was distilled off under reduced pressure. The residue was purified by silica gel chromatography (eluent: ethyl acetate/n-heptane= 1/9 by volume) to give a mixture (2.4 g) of 1-(3-butylcyclopent-1-enyl)-4-ethoxy-2,3-difluorobenzene and 1-(4-butylcyclopent-1-enyl)-4-ethoxy-2,3-difluorobenzene.

Source