Sodium hydride → Tert-butyl 4-[4-(2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethoxy)phenyl]piperazine-1-carboxylate

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Reaction Conditions

Reaction Steps

Tert-butyl 4-(4-hydroxyphenyl)piperazine-1-carboxylate (2.01 g, 7.23 mmol) was dissolved in DMF (20 ml). To the solution, sodium hydride (320 mg, 8 mmol) was added at room temperature, and the solution was stirred for 20 minutes at 70° C. To the solution, 2-chloro-1-(2-methyloxiran-2-ylmethyl)-4-nitroimidazole prepared in Example 6 (1.5 g, 7.23 mmol) was added with cooling on ice-bath, and the solution was stirred for further 20 minutes at 80° C. To the reaction mixture, ice-water was added, and the solution was stirred vigorously. The precipitates were filtered off, washed with water and dissolved in methylene chloride. The solution was washed with a saturated saline solution, dried over magnesium sulfate and then filtered. The resulting filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (methylene chloride/ethyl acetate=20/1) and then crystallized from methylene chloride/ethyl acetate to afford tert-butyl 4-[4-(2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethoxy)phenyl]piperazine-1-carboxylate (1.5 g, yield 45%) as a white powder.

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