Sodium hydride → Tert-butyl 4-[2-(2,3-dihydro-6-nitrospiro[imidazo[2,1-b]oxazol-2,4'-piperidin]-1'-yl)-2-oxoethyl]piperazine-1-carboxylate

Participants

Reaction Steps

Tert-butyl 4-{2-[4-(2-chloro-4-nitroimidazol-1-ylmethyl)-4-hydroxypiperidin-1-yl]-2-oxoethyl}-piperazine carboxylate prepared in Example 650 (2.58 g, 5.3 mmol) was dissolved in dioxane (30 ml). To the solution, sodium hydride (254 mg, 6.36 mmol) was added with cooling on ice-bath followed by stirring under reflux overnight. The reaction mixture was concentrated under reduced pressure. To the residue, ice-water and ethyl acetate were added followed by stirring vigorously. The precipitates were filtered off, washed with water and ethyl acetate, and then dried under reduced pressure to afford tert-butyl 4-[2-(2,3-dihydro-6-nitrospiro[imidazo[2,1-b]oxazol-2,4′-piperidine]-1′-yl)-2-oxoethyl]piperazine-1-carboxylate (996 mg, yield 42%) as a white powder.

Provenance & Evidence