To a stirred solution of thionyl chloride (5 mL, 68.55 mmol) in methylene chloride (100 mL) at ˜10° C. was slowly added 3-(1-ethylpropyl)-1H-pyrazole (11.74 g, 84.94 mmol). The resulting solution was stirred for ˜20 minutes and was then cooled to ˜0° C. To this solution was added N,N-diisopropylethylamine (24.7 mL, 141.8 mmol) dropwise and then 5-hydroxy-3-[3-(trifluoromethyl)phenyl]-4-oxazolidinone (14 g, 56.64 mmol), portionwise at temperatures between 0° C. and 15° C. After the addition, the reaction mixture was allowed to warm to room temperature, and then stirred at room temperature for 2 days. To the reaction mixture was then added concentrated aqueous sodium bicarbonate solution (100 mL). The methylene chloride layer was separated, and the aqueous layer was extracted twice with methylene chloride (˜100 mL each). The methylene chloride layers were combined, dried over MgSO4 and then concentrated. The residue was loaded on silica gel in a column and eluted with methylene chloride to give a crude product. The crude product was further purified by trituration in hexanes followed by filtration to give the title compound, a compound of this invention, as a white solid (10.67 g) melting at 83–85° C.
