Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1) → (1R)-1-[2-(2,4-difluorophenyl)-2-oxiranyl]ethanol

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Reaction Steps

In 600 ml of ethanol were dissolved 82 g of 2-(2,4-difluorophenyl)-2-[(1R)-1-(3,4,5,6-tetrahydro-2H-pyran-2-yl)oxyethyl]oxirane (prepared by a method disclosed in Japanese Patent Application Laid-open No. 74168/1992, JP-A-4-74168) and 6.3 g of pyridinium p-toluenesulfonate, and the solution was stirred at 55° C. for 1 hour. The reaction mixture was concentrated under reduced pressure. The residue was dissolved in 1 liter of ethyl acetate, and washed twice, each time with 200 ml of water. The aqueous phase was extracted twice, each time with 100 ml of ethyl acetate. The organic phases were collected, washed with saturated aqueous solution of sodium chloride, dried over magnesium sulfate and the solvent was distilled off under reduced pressure. The residue was purified with using silica gel chromatography (gradient eluent; hexane:ethyl acetate=10:1→8:1→3:1) to give 31.5 g of (1R)-1-[2-(2,4-difluorophenyl)-2-oxiranyl]ethanol as a pale yellow oil.

Provenance & Evidence