Triethylamine → (S)-4-(2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl)piperazine-1-carboxylic acid cyclohexylamide

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Reaction Steps

(S)-2-Methyl-6-nitro-2-(piperazin-1-ylmethyl)-2,3-dihydroimidazo[2,1-b]oxazole dihydrochloride prepared in Example 408 (236 mg, 0.88 mmol) was dissoloved in a mixture of methylene chloride (15 ml) and triethylamine (2 ml, 14.35 mmol). To the solution, cyclohexyl isocyanate (120 mg, 0.96 mmol) was added followed by stirring at room temperature for 1 hour. The reaction mixture was washed with water and a saturated saline solution, dried over sodium sulfate and then filtered. The filtrate was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (methylene chloride/methanol=20/1) to afford (S)-4-(2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl)piperazine-1-carboxylic acid cyclohexylamide (164 mg, 47%) as a light yellow powder.

Provenance & Evidence