反应详情

To the solution of (R)-3-(2-chloro-4-nitroimidazol-1-yl)-2-hydroxy-2-methylpropyl 4-(4-trifluoromethylphenylamino)piperidine-1-carboxylate prepared in Example 105 (1.44 g, 2.85 mmol) in DMF (10 ml), sodium hydride (0.14 g, 3.42 mmol) was added followed by stirring for 1 hour with cooling on ice-bath. To the reaction mixture, ice-water was added, and the solution was extracted with ethyl acetate. The organic phase was washed with water, dried over magnesium sulfate and then concentrated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate) and recrystallized from acetonitrile-isopropanol to afford (R)-2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl 4-(4-trifluoromethylphenylamino)piperidine-1-carboxylate (0.42 g, yield 31%) as a white solid.

1. temperaturewith cooling on ice-bath
2. extractionthe solution was extracted with ethyl acetate
3. washThe organic phase was washed with water
4. dry with materialdried over magnesium sulfate
5. concentrationconcentrated under reduced pressure
6. customThe residue was purified by silica gel column chromatography (ethyl acetate)
7. customrecrystallized from acetonitrile-isopropanol