Reaction #1973899

Reaction equation

compound ( 9 )

8-(4-butoxy-2,3-difluorophenyl)-1,4-dioxaspiro[4.5]decan-8-ol

p-toluenesulfonic acid

→

8-(4-butoxy-2,3-difluorophenyl)-1,4-dioxaspiro[4.5]decane

Yield 91.2%

Solvents

toluene

Conditions

Workup

1. 1
   Temperaturethe mixture was heated
2. 2
   Temperatureto reflux for 2 hours
3. 3
   workup.DISTILLATIONwhile distilled water
4. 4
   Otherwas removed
5. 5
   workup.ADDITIONwater (500 ml) and toluene (900 ml) were added to the mixture
6. 6
   workup.ADDITIONmixed with it
7. 7
   Otherhad separated into two phases of organic and aqueous phases
8. 8
   Extractionthe extraction into an organic phase
9. 9
   OtherThe resulting organic phase was separated
10. 10
    Washwashed successively with a saturated aqueous solution of sodium hydrogencarbonate and water
11. 11
    Dryingdried over anhydrous magnesium sulfate
12. 12
    OtherThe resulting solution was purified with a fractional operation by means of column chromatography
13. 13
    workup.DISSOLUTIONThe product was dissolved in a mixed solvent of toluene (150 ml) and Solmix A-11 (150 ml), and palladium on carbon (3.0 g)
14. 14
    workup.ADDITIONwas added
15. 15
    OtherAfter the completion of the reaction, palladium on carbon
16. 16
    Otherwas removed
17. 17
    workup.DISTILLATIONthe solvent was distilled off
18. 18
    OtherThe resulting residue was purified with a fractional operation by means of column chromatography
19. 19
    OtherThe product was further purified by recrystallization from Solmix A-11

Procedure

The compound (9) (55.0 g), p-toluenesulfonic acid (1.8 g) and toluene (300 ml) were mixed and the mixture was heated to reflux for 2 hours, while distilled water was removed. After the reaction mixture had been cooled to 30° C., water (500 ml) and toluene (900 ml) were added to the mixture and mixed with it. The mixture was then allowed to stand until it had separated into two phases of organic and aqueous phases, and the extraction into an organic phase was carried out. The resulting organic phase was separated, and washed successively with a saturated aqueous solution of sodium hydrogencarbonate and water, and then dried over anhydrous magnesium sulfate. The resulting solution was purified with a fractional operation by means of column chromatography using silica gel as a stationary phase powder and toluene as an eluent. The product was dissolved in a mixed solvent of toluene (150 ml) and Solmix A-11 (150 ml), and palladium on carbon (3.0 g) was added and then the mixture was stirred at room temperature under an atmosphere of hydrogen until hydrogen absorption had ceased. After the completion of the reaction, palladium on carbon was removed and the solvent was distilled off. The resulting residue was purified with a fractional operation by means of column chromatography using silica gel as a stationary phase powder and heptane as an eluent. The product was further purified by recrystallization from Solmix A-11 to give 8-(4-butoxy-2,3-difluorophenyl)-1,4-dioxaspiro[4.5]decane (10) (47.8 g). The yield based on the compound (9) was 84.0%.

Source