Methyl butyrate → (2R,3S)-2-(2,4-difluorophenyl)-3-mercapto-1-(1H-1,2,4-triazol-1-yl)-2-butanol

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Reaction Steps

In methanol (25 ml) were dissolved (2R,3R)-2-(2,4-difluorophenyl)-3-methyl-2-[(1H-1,2,4-triazol-1-yl)-methyl]oxirane (0.98 g), methyl 3-mercaptopropionate (3.3 ml) and 28% sodium methoxide-methanol (3.0 g) and the solution was refluxed on an oil bath. After 2 and after 3 hours, methyl 3-methylpropionate (0.83 ml) and 28% sodium methoxide-methanol (0.75 g) were added at each time. The oil bath was removed after heating for 4 hours and the reaction mixture was neutralized with cold 1N-HCl (23.4 ml) and extracted with dichloromethane (200 ml). The extract was washed with saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate and the solvent was distilled off under reduced pressure. The residue was purified by silica gel chromatography (eluent: hexane-ethyl acetate=1:3). The desired fraction was concentrated and the resulting crystals were recrystallized from ethyl acetate-hexane to give (2R,3S)-2-(2,4-difluorophenyl)-3-mercapto-1-(1H-1,2,4-triazol-1-yl)-2-butanol (compound 118, 461 mg) as colorless needles. m.p. 141°-143° C.

Provenance & Evidence