3,5-Dinitrobenzoic acid → [(1S)-1-[(2R)-2-(2-fluorophenyl)-2-oxiranyl)ethyl] 3,5-dinitrobenzoate

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Reaction Steps

2-(2-Fluorophenyl)-2-[(1R)-1-(3,4,5,6-tetrahydro-2H-pyran-2-yl)oxyethyl]oxirane (synthesized by the method described in EP0548553A) was converted into (1R)-1-[2-(2-fluorophenyl)-2-oxiranyl]ethanol by the method described in Reference Example 1. To an ice-cooled solution of this compound (34.77 g) in tetrahydrofuran (600 ml) were added triphenylphosphine (127.21 g), 3,5-dinitrobenzoic acid (102.88 g) and diethyl azodicarboxylate (84.47 g). The mixture was stirred at room temperature for 7 hours under an argon atmosphere, and then ethyl acetate (600 ml), diisopropyl ether (100 ml) and water (800 ml) were added. The separated aqueous layer was extracted with ethyl acetate (600 ml, 400 ml). The organic layers were combined, washed with water and a saturated aqueous solution of sodium chloride successively, dried over anhydrous magnesium sulfate and concentrated. The residue was purified by silica gel chromatography (eluent:hexane/ethyl acetate=5/1) and recrystallized from ethyl acetate to give [(1S)-1-[(2R)-2-(2-fluorophenyl)-2-oxiranyl]ethyl] 3,5-dinitrobenzoate (23.15 g) as colorless needles.

Provenance & Evidence