Reaktion #4838

Reaktionsgleichung

acetic anhydride

4-[2,2,2-trifluoro-1-hydroxy-1-(trifluoromethyl)ethyl]toluene

sulfuric acid

acetic anhydride

→

α,α -bis-acetyloxy-4-[1-(acetyloxy)-2,2,2-trifluoro-1-(trifluoromethyl)ethyl]toluene

Lösungsmittel

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGAfter stirring
2. 2
   Sonstigethe resulting reaction mixture
3. 3
   Sonstigeto obtain an aqueous mixture which
4. 4
   workup.WAITto stand for 18 hours
5. 5
   SonstigeWater is decanted from the oily solid
6. 6
   workup.DISSOLUTIONThe solid is dissolved in ether
7. 7
   Sonstigeto obtain a solution which
8. 8
   Waschenis washed with water and sodium bicarbonate solution
9. 9
   Trocknendried with anhydrous magnesium sulfate
10. 10
    Filtrationfiltered
11. 11
    Sonstigeevaporated at reduced pressure
12. 12
    Sonstigeto give an oily solid
13. 13
    SonstigeThe solid is triturated with ether
14. 14
    Filtrationfiltered
15. 15
    Sonstigerecrystallized from chlorobutane

Vorschrift

To a solution of 156 g (0.60 mole) of 4-[2,2,2-trifluoro-1-hydroxy-1-(trifluoromethyl)ethyl]toluene in 675 ml of acetic anhydride is added 135 ml of concentrated sulfuric acid at 0°. To the solution stirred at 0° is added a soluton of 168 g (1.68 mole) of chromium trioxide in 750 ml of acetic anhydride dropwise over a two-hour period. After stirring is continued for an additional two hours, the resulting reaction mixture is poured into five liters of ice and is diluted with five liters of water to obtain an aqueous mixture which is allowed to stand for 18 hours. An oily solid with water above it is obtained. Water is decanted from the oily solid. The solid is dissolved in ether to obtain a solution which is washed with water and sodium bicarbonate solution, dried with anhydrous magnesium sulfate, filtered and evaporated at reduced pressure to give an oily solid. The solid is triturated with ether, filtered and recrystallized from chlorobutane to give 60 g of α,α -bis-acetyloxy-4-[1-(acetyloxy)-2,2,2-trifluoro-1-(trifluoromethyl)ethyl]toluene, m.p. 93°-94.6°.

Quelle