Acetic Anhydride → 1-acetyl-4-[(2R,3R)-3-(2,4-difluorophenyl)-3-hydroxy-4-(1H-1,2,4-triazol-1-yl)-2-butylsulfonyl]piperazine

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Reaction Steps

In dichloromethane (10 ml) was dispersed 1[(2R,3R)-3-(2,4-difluorophenyl)-3-hydroxy-4-(1H ,1,2,4-triazol-1-yl)-2-butylsulfonyl]piperazine.dihydrochloride (Compound 20, 0.40 g) obtained in Working Example 14. To the dispersion were added, under ice-cooling, triethylamine (0.40 ml) and acetic anhydride (0.13 g). The mixture was stirred for 30 minutes under ice-cooling. The reaction mixture was then washed with water, dried and concentrated. The concentrated was subjected to a silica gel chromatography (eluent: dichloromethane/methanol=20/1) for purification. The object fraction was concentrated and processed with hydrogen chloride, followed by addition of isopropyl ether to give 1-acetyl-4-[(2R,3R)-3-(2,4-difluorophenyl)-3-hydroxy-4-(1H-1,2,4-triazol-1-yl)-2-butylsulfonyl]piperazine (Compound 25).hydrochloride (336 mg) as colorless powder.

Provenance & Evidence