Hydrochloric Acid → (S)-2-(2,4-difluorophenyl)-1-isobutyryloxy-3-methanesulfonyloxy-2-propanol

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Reaction Steps

Into a solution wherein 12 g of (R)-2-(2,4-difluorophenyl)-3-isobutyryloxy-1,2-propanediol obtained in Example 40 was dissolved in 120 ml of ethyl acetate was added dropwise 10 g of methanesulfonyl chloride at a temperature of 0° to 5° C., and thereto was added dropwise 6.92 g of pyridine at a temperature of 0° to 5° C. After dropping, the resulting liquid was stirred at room temperature for 16 hours. To the reaction mixture was added 400 ml of 1N hydrochloric acid and an organic layer separated. The organic layer was washed with saturated aqueous solution with sodium hydrogencarbonate and with saturated aqueous solution with sodium chloride, and dried over anhydrous sodium sulfate. The solvent was removed trader reduced pressure and the residue was purified by column chromatography on silica gel (eluent: n-hexane/ethyl acetate=1/1) to give 15.2 g of oily (S)-2-(2,4-difluorophenyl)-1-isobutyryloxy-3-methanesulfonyloxy-2-propanol. An optical purity thereof was determined in the same manner as in Example 35. (Elution time: 22.5 minutes ((R)-form) and 24.7 minutes ((S)-form)). 1H-NMR (400 MHz, CDCl3) δ ppm: 7.71-7.68 (1H, m), 6.96-6.92 (1H, m), 6.85-6.81 (1H, m), 4.59-4.47 (4H, m), 3.04 (3H, s), 2.51-2.48 (1H, m), 1.06-1.04 (6H, m) Optical purity: 96.0% ee

Provenance & Evidence