3,5-Dinitrobenzoyl chloride → [(1R)-1-[(2R)-2-(2,4-Difluorophenyl)-2-oxiranyl]ethyl]3,5-dinitrobenzoate

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Reaction Steps

(1R)-1-[2-(2,4-Difluorophenyl)-2-oxiranyl]ethanol (31.5 g) and 3,5-dinitrobenzoyl chloride (40 g) were dissolved in methylene chloride (500 ml), to which trimethylamine (24.1 ml) was added dropwise at ice-bath temperature. After the mixture was stirred at room temperature for 3.5 hours, it was washed with water (150 ml) and 5% sodium bicarbonate aqueous solution successively, dried over magnesium sulfate and concentrated under reduced pressure. The precipitated crystals were filtrated and washed with methylene chloride. The mother liquor and the washings were combined and distilled off under reduced pressure. Ethyl acetate (25 ml) and methanol (300 ml) were added to the residue, and the mixture was cooled in an ice bath. The precipitated crystals were collected by filtration and recrystallized from a mixture of ethyl acetate (25 ml) and methanol (250 ml) to give [(1R)-1-[(2R)-2-(2,4-difluorophenyl)-2-oxiranyl]ethyl] 3,5-dinitrobenzoate (28.7 g) as colorless needles.

Provenance & Evidence