Triethylamine → (2S,3R)-2-(2,4-difluorophenyl)-3-methanesulfonyloxy-1-(1H-1,2,4-triazol-1-yl)-2-butanol

Beteiligte Stoffe

Reaktionsschritte

In ethyl acetate (40 ml) was dissolved (2S,3R)-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2,3-butanediol (2.5 g). To the solution were added, under ice-cooling, triethylamine (1.82 ml) and methanesulfonyl chloride (1.51 g). The mixture was stirred for 30 minutes at room temperature. To the reaction mixture was added ethyl acetate (40 ml), which was washed with water and dried (anhydrous magnesium sulfate), followed by concentration to give (2S,3R)-2-(2,4-difluorophenyl)-3-methanesulfonyloxy-1-(1H-1,2,4-triazol-1-yl)-2-butanol as an oily product. This product was dissolved in methanol (40 ml), to which was added, under ice-cooling, a 28% methanol solution of sodium methylate (2.04 g). The mixture was stirred for 30 minutes at room temperature, then the reaction mixture was concentrated under reduced pressure. To the concentrate was added ethyl acetate (100 ml), which was washed with water, followed by drying (anhydrous magnesium sulfate). The solvent was distilled off under reduced pressure, and the residue was purified by means of a silica gel chromatography (eluent: ethyl acetate-dichloromethane=4:1) to give (2S,3S)-2-(2,4-difluorophenyl)-3-methyl-2-[(1H-1,2,4-triazol-1-yl)methyl]oxirane (1.62 g) as a colorless oily product. This product became a colorless solid in a freezer. m.p. 41°-43° C. [α]D23 =+5.8° (c=1.0 in methanol)

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