Reaktion #1462219

Reaktionsgleichung

sodium hydroxide

Lithium aluminum hydride

(3R)-1-benzyl-3-(4-hydroxy-3-methoxybenzyl)piperazine-2,5-dione

3,5-bis(trifluoromethyl)benzoyl chloride

→

3,5-bis(trifluoromethyl)benzoate

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

Lösungsmittel

water

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturunder reflux for 5 hours
2. 2
   Temperaturcooling
3. 3
   workup.STIRRINGAfter being stirred for 30 minutes
4. 4
   Extraktionthe resulting mixture was extracted with ethyl acetate
5. 5
   SonstigeThe organic layer was separated
6. 6
   Trocknendried over magnesium sulfate
7. 7
   Sonstigeevaporated under reduced pressure
8. 8
   SonstigeThe residue was purified by column chromatography on silica gel using
9. 9
   workup.ADDITIONa mixture of hexane and ethyl acetate (4:1)

Vorschrift

Lithium aluminum hydride (614 mg) was added to a suspension of (3R)-1-benzyl-3-(4-hydroxy-3-methoxybenzyl)piperazine-2,5-dione (1.1 g) in tetrahydrofuran (40 ml) at room temperature. After being stirred under reflux for 5 hours, the reaction mixture was treated with 2N sodium hydroxide (5 ml) under nitrogen atmosphere. The whole mixture was diluted with water (40 ml) and thereto 3,5-bis(trifluoromethyl)benzoyl chloride (1.6 ml) was added dropwise under ice-cooling. After being stirred for 30 minutes, the resulting mixture was extracted with ethyl acetate. The organic layer was separated, dried over magnesium sulfate and evaporated under reduced pressure. The residue was purified by column chromatography on silica gel using a mixture of hexane and ethyl acetate (4:1) to give the objective (2R)-4-benzyl-1-[3,5-bis(trifluoromethyl)benzoyl]-2-(4-hydroxy-3-methoxybenzyl)piperazine and its 3,5-bis(trifluoromethyl)benzoate, which was converted to the objective compound by treatment with a mixture of 1N sodium hydroxide and methanol.

Quelle