反应详情

To the solution of (R)-3-(2-chloro-4-nitroimidazol-1-yl)-2-hydroxy-2-methylpropyl 4-tertbutoxycarbonylpiperazine-1-carboxylate prepared in Example 87 (4.12 g, 9.20 mmol) in DMF (30 ml), sodium hydride (0.44 g, 11.04 mmol) was added followed by stirring for 1 hour with cooling on ice-bath. Ice-water was added to the reaction mixture, and the precipitates were filtered off, purified by silica gel column chromatography (ethyl acetate) and then washed with isopropanol to afford (R)-2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl 4-tertbutoxycarbonylpiperazine-1-carboxylate (2.24 g, yield 59%) as a white solid.

1. temperaturewith cooling on ice-bath
2. filtrationthe precipitates were filtered off
3. custompurified by silica gel column chromatography (ethyl acetate)
4. washwashed with isopropanol