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

Participants

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 dissolved in a mixture of methylene chloride (5 ml) and triethylamine (2 ml, 14.35 mmol). To the solution, a mixture of 4-aminobenzotrifluoride (142 mg, 0.882 mmol), 1,1′-carbonyldiimidazole (143 mg, 0.882 mmol) and DMF (6 ml) stirred at room temperature overnight was added followed by stirring at room temperature for 6 hours. To the reaction mixture, water was added, and the mixture was extracted with ethyl acetate. The organic phase was washed with water three times 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=30/1) to afford (S)-4-(2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl)piperazine-1-carboxylic acid (4-trifluoromethylphenyl)amide (90 mg, yield 23%) as a white powder.

Provenance & Evidence