Ethanol → (+)-2-[4-(2-fluoro-9-hydroxy-9-trifluoromethyl-9H-fluoren-4-yl)-pyrazol-1-yl]-2-methyl-propane-1,3-diol

Participants

Reaction Steps

To a solution of an optically active form (26.6 g) of 2-[4-(2-fluoro-9-hydroxy-9-trifluoromethyl-9H-fluoren-4-yl)-pyrazol-1-yl]-3-hydroxy-2-methyl-propionic acid in tetrahydrofuran (40 ml) was added dropwise at room temperature a 1.09M solution (200 ml) of borane-tetrahydrofuran complex in tetrahydrofuran, and the mixture was stirred for 3 hr. To the reaction mixture was added dropwise ethanol (25 ml) at room temperature and the mixture was stirred at 80° C. for 1 hr. To this mixture were added water (200 ml) and saturated aqueous sodium hydrogen carbonate (100 ml) and the mixture was extracted twice with ethyl acetate (100 ml). The combined organic layer was successively washed twice with water (100 ml) and once with saturated brine (100 ml), dried over anhydrous sodium sulfate and concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (eluent: chloroform/methanol=20/1 to 10/1) to give the title compound (17.4 g).

Provenance & Evidence