Réaction #707507

Équation de réaction

sodium borohydride

potassium hydroxide

rac-(2S*)-2-[(R*)-4-chloro-α-(nitromethyl)benzyl]cyclohexanone

→

rac-(1S*)-2-[(R*)-4-chloro-α-(nitromethyl)benzyl]cyclohexanol

Solvants

water

ether pentane

water

water

methanol

Conditions de réaction

Traitement

1. 1
   Autredoes not exceed 5°
2. 2
   workup.DISTILLATIONAfter treatment with 12 ml of acetic acid the solvent is distilled off
3. 3
   AutreThe residue obtained
4. 4
   Extractionis extracted twice with 200 ml of ether each time
5. 5
   LavageThe organic phase is washed with water
6. 6
   Séchagedried over magnesium sulphate
7. 7
   Autreevaporated
8. 8
   AutreThe oil obtained
9. 9
   workup.WAITleft
10. 10
    Autrethe crystalline product obtained
11. 11
    Autreis recrystallized from ether/hexan

Mode opératoire

A solution of 6.8 g (121 mmol) of potassium hydroxide in 40 ml of water is added dropwise while cooling within about 30 minutes to a solution of 28.2 g (100 mmol) of rac-(2S*)-2-[(R*)-4-chloro-α-(nitromethyl)benzyl]cyclohexanone in 200 ml of methanol so that the temperature does not exceed 5°. An ice-cold solution of 2.85 g (75 mmol) of sodium borohydride in 20 ml of water is subsequently added dropwise, whereupon the mixture is stirred at 0° for 3 hours. After treatment with 12 ml of acetic acid the solvent is distilled off. The residue obtained is treated with water, whereupon the mixture is extracted twice with 200 ml of ether each time. The organic phase is washed with water, dried over magnesium sulphate and evaporated. The oil obtained is taken up in ether/pentane, left to stand in a refrigerator and the crystalline product obtained is recrystallized from ether/hexan. There is obtained rac-(1S*)-2-[(R*)-4-chloro-α-(nitromethyl)benzyl]cyclohexanol of m.p. 82°-84°.

Source