To a solution of 4-(4-chlorophenyl)-5-(3-hydroxypropyl)-2-(2-methylimidazol-1-yl)oxazole (509 g), triethylamine (254.6 mL) in toluene (4072 mL) was added dropwise methanesulfonyl chloride (136.4 mL) at not higher than 10° C. Ten minutes later, o-cresol (248.0 mL) and tetrabutylammonium bromide (25.8 g) were added to the obtained mixture and a solution of NaOH (255 g) in water (1018 mL) was further added. The mixture was heated under reflux for 1 h. After cooling, the toluene layer was separated and washed with 1N aqueous NaOH solution (4072 mL×3) and then with 5% aqueous NaCl solution. The solvent was evaporated and the obtained crystals were recrystallized from ethanol-water (9:1) to give the title compound (595.6 g, yield: 91.2%).
