Citric Acid → HCID 20741411, compound

Participants

Reaction Steps

Under ice cooling, triethylamine (0.46 ml) and methanesulfonyl chloride (217 μl, 2.80 mmol) were added to a dichloromethane (10 ml) solution of 4-(R)-[1-hydroxy-1-phenylmethyl]-1-[1-(R)-phenylethyl]-2-pyrrolidone [F1] (738 mg, 2.50 mmol), followed by stirring at the same temperature for 1 hour. To the reaction solution was added 10% citric acid (20 ml) under ice cooling, and the mixture was extracted with chloroform (30 ml×2). After washing with saturated saline (100 ml), the organic layer was dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure, and the residue was dissolved in N,N-dimethylformamide (10 ml). Then, sodium azide (488 mg, 7.50 mmol) was added thereto, followed by stirring at 60° C. for 1.5 hours. After cooling on standing, water (50 ml) was added to the reaction solution and the resulting mixture was extracted with ethyl acetate (70 ml×3). The organic layer was washed with saturated saline (150 ml) and dried over anhydrous sodium sulfate. After removal of the solvent under reduced pressure, the residue was subjected to silica gel column chromatography. Elution with n-hexane/ethyl acetate (3/2) afforded the title compound (701 mg, 87%) as a colorless oil.

Provenance & Evidence