Reaktion #671370

Reaktionsgleichung

sodium bicarbonate

(2R)-1-[3,5-bis(trifluoromethyl)benzoyl]-2-(3,4-dimethylbenzyl)piperazine

4-formyl-1-(triphenylmethyl)pyrazole

sodium triacetoxyborohydride

→

(2R)-1-[3,5-bis(trifluoromethyl)benzoyl]-2-(3,4-dimethylbenzyl)-4-(4-pyrazolylmethyl)piperazine

Ausbeute 64.9%

Lösungsmittel

1,2-dichloroethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionthe mixture was extracted with ethyl acetate
2. 2
   WaschenThe extract was washed with brine
3. 3
   Trocknendried over magnesium sulfate
4. 4
   Sonstigeevaporated under reduced pressure
5. 5
   workup.DISSOLUTIONThe resulting residue was dissolved in dichloromethane (40 ml)
6. 6
   workup.ADDITIONadded to a mixture of trifluoroacetic acid (30 ml) and anisole (15 ml)
7. 7
   workup.STIRRINGAfter stirring for 7.5 hours at room temperature
8. 8
   Sonstigethe mixture was quenched with 10% sodium hydroxide (150 ml) and aqueous sodium bicarbonate
9. 9
   Extraktionextracted with dichloromethane
10. 10
    WaschenThe extract was washed with aqueous sodium bicarbonate solution and brine successively
11. 11
    Trocknendried over magnesium sulfate
12. 12
    Sonstigeevaporated under reduced pressure
13. 13
    SonstigeThe residue was purified by column chromatography on silica gel using
14. 14
    workup.ADDITIONa mixture of ethyl acetate and hexane (3:7)

Vorschrift

To a mixture of (2R)-1-[3,5-bis(trifluoromethyl)benzoyl]-2-(3,4-dimethylbenzyl)piperazine (3.71 g) and 4-formyl-1-(triphenylmethyl)pyrazole (3.66 g) in 1,2-dichloroethane (80 ml) was added sodium triacetoxyborohydride (2.86 g). After stirring at room temperature for 3 hours, aqueous sodium bicarbonate solution was added to the mixture and the mixture was extracted with ethyl acetate. The extract was washed with brine, dried over magnesium sulfate and evaporated under reduced pressure. The resulting residue was dissolved in dichloromethane (40 ml) and added to a mixture of trifluoroacetic acid (30 ml) and anisole (15 ml). After stirring for 7.5 hours at room temperature, the mixture was quenched with 10% sodium hydroxide (150 ml) and aqueous sodium bicarbonate and extracted with dichloromethane. The extract was washed with aqueous sodium bicarbonate solution and brine successively, dried over magnesium sulfate, and evaporated under reduced pressure. The residue was purified by column chromatography on silica gel using a mixture of ethyl acetate and hexane (3:7) to give (2R)-1-[3,5-bis(trifluoromethyl)benzoyl]-2-(3,4-dimethylbenzyl)-4-(4-pyrazolylmethyl)piperazine (2.84 g).

Quelle