1,1'-Carbonyldiimidazole → (3R,4R)-4-(2,5-Difluorophenyl)-3-methyl-4-(1H-1,2,4-triazol-1-ylmethyl)-2-oxetanone

10 g (27 mmol) of (2R,3R)-3-(2,5-difluorophenyl)-3-hydroxy-2-methyl-4-[1,2,4]-triazol-1-yl-butyric acid (oxalate salt) were dissolved in 200 ml of tetrahydrofuran and after addition of 5.8 g (35 mmol) 1,1′-carbonyldiimidazole stirred at 60° C. for 3 hours. After evaporation of the solvent the reaction mixture was poured onto 300 ml of aqueous 0.5N-HCl and extracted 3 times with each 300 ml of ethyl acetate. The extract was dried over Na2SO4 and evaporated. 7.1 g (94% yield) of (3R,4R)-4-(2,5-difluoro-phenyl)-3-methyl-4-[1,2,4]triazol-1-ylmethyl-oxetan-2-one resulted.