Suspension of 2- bromo- 4- nitroimidazole (100 g), 2- methyl- 2- oxiranylmethyl (S)- 4- nitrobenzenesulfonate (142.4 g), potassium carbonate (93.6 g), caesium fluoride (15.8 g) and dimethylformamide (420 ml) was stirred at 35- 40°C for 26 hours. The reaction mixture was poured into water (1.2 litres) and then extracted twice with ethyl acetate (1 litre). The ethyl acetate layers were combined after being washed twice with water (1.2 liters), washed with an aqueous solution (800 ml) saturated with sodium chloride, then dried over anhydrous magnesium sulfate. After being filtrated under reduced pressure, the filtrate was concentrated under a reduced pressure. The thus obtained residue was purified by use of a silica gel column chromatography (eluent: n-hexane/ ethyl acetate = 1/1), there was obtained (R)-2-bromo-1-(2-methyl-2-oxiranylmethyl)-4-nitroimidazole (110.9 g, yield: 81%) as a yellow powdery product.
