Methyl 3-mercaptopropionate → 2-(2,4-Difluorophenyl)-3-mercapto-1-(1H-1,2,4-triazol-1-yl)-2-butanol

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Reaction Steps

In methanol (10 ml) were dissolved (2R,3S)-2-(2,4-difluorophenyl)-3-methyl-2-[(1H-1,2,4-triazol-1-yl)methyl]oxirane (0.40 g), methyl 3-mercaptopropionate (1.42 ml) and 28% sodium methoxide-methanol (1.25 ml) and the solution was refluxed. After 2 and after 3.5 hours, (0.53 ml and 0.32 ml each of) methyl 3-mercaptopropionate were added, and after 2.5 minutes, 28% sodium methoxide-methanol (0.63 ml) was added. At 4.5 hours after the beginning of heating, the oil bath was removed and the reaction mixture was cooled, neutralized with 1N hydrochloric acid (9.6 ml) and extracted with dichloromethane (100 ml). The extract was washed with saturated aqueous sodium chloride solution (20 ml) and dried over anhydrous sodium 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 collected and washed with isopropyl ether to give (2R,3R)-2-(2,4-difluorophenyl)-3-mercapto-1-(1H-1,2,4-triazol-1-yl)-2-butanol (compound 43:0.22 g) as colorless needles. m.p. 176°-178° C.

Provenance & Evidence