Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1) → (2RS,3RS)-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2,3-butanediol

Participants

Reaction Conditions

Reaction Steps

In ethanol (500 ml) was dissolved 2-(2,4-difluorophenyl)-3-(3,4,5,6-tetrahydro-2H-pyran-2-yl)oxy-1-(1H-1,2,4-triazol-1-yl)-2-butanol (51.4 g), to which was added pyridinium p-toluenesulfonate (13.2 g), and the mixture was stirred for 6 hours at 55° C. To the resultant mixture was further added pyridinium p-toluenesulfonate (2.0 g), which was stirred for 1.5 hour at 55° C. The mixture was cooled, then the solvent was distilled off under reduced pressure. To the residue was added ethyl acetate (900 ml), and the mixture was washed with water (50 ml) three times. The ethyl acetate layer was dried over anhydrous magnesium suflate, then the solvent was distilled off. To the residue were added ethyl acetate (50 ml) and ethyl ether (100 ml). Precipitating crystals were collected by filtration to afford pure (99% purity) (2RS,3RS)-2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2,3-butanediol (29.0 g) as diastereomer, m.p. 154°-156° C.

Provenance & Evidence