Reaction #2175431

Reaction equation

ammonia

Lithium aluminum hydride

1-(4′-Ethoxy-2,2′,3,3′-tetrafluoro-1,1′-biphenyl-4-yl)-cyclohexan-4-one

ethyl acetate

→

trans-4-(4′-ethoxy-2,2′,3,3′-tetrafluoro-1,1′-biphenyl-4-yl)-cyclohexanol

Solvents

THF

THF

Conditions

Workup

1. 1
   workup.ADDITIONwas added dropwide to the suspension in the temperature range of −20° C. to −10° C.
2. 2
   Temperaturecooling
3. 3
   Otherdeposits were removed by filtration through Celite
4. 4
   ExtractionThe filtrate was extracted with ethyl acetate
5. 5
   WashThe combined organic phase was washed successively with water and brine
6. 6
   Dryingdried over anhydrous magnesium sulfate
7. 7
   workup.DISTILLATIONThe solvent was distilled off under reduced pressure
8. 8
   Otherthe residue was purified by recrystallization from heptane

Procedure

Lithium aluminum hydride (0.31 g) was suspended in THF (100 ml). 1-(4′-Ethoxy-2,2′,3,3′-tetrafluoro-1,1′-biphenyl-4-yl)-cyclohexan-4-one (s-27) (5.0 g) dissolved in THF (20 ml) was added dropwide to the suspension in the temperature range of −20° C. to −10° C., and the stirring was continued in this temperature range for another 2 hours. After the completion of the reaction had been confirmed by means of GC analysis, ethyl acetate and then a saturated aqueous solution of ammonia were added to the reaction mixture under ice-cooling and deposits were removed by filtration through Celite. The filtrate was extracted with ethyl acetate. The combined organic phase was washed successively with water and brine, and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure and the residue was purified by recrystallization from heptane to give trans-4-(4′-ethoxy-2,2′,3,3′-tetrafluoro-1,1′-biphenyl-4-yl)-cyclohexanol (s-28) (12.1 g). The yield based on the compound (s-27) was 89.1%.

Source