Trifluoroacetic acid → HCID 69635392, compound

Participants

Reaction Steps

Tert-butyl (S)-4-[2-(N-methyl-2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethylamino)-ethyl]piperazine-1-carboxylate prepared in Example 173 (300 mg, 0.71 mmol) was dissolved in methylene chloride (5 ml). To the solution, trifluoroacetic acid (5 ml) was added followed by stirring at room temperature for 3 hours. The reaction mixture was concentrated under reduced pressure and added methylene chloride (2 ml) and triethylamine (2 ml). After stirring for 5 minutes at room temperature, the solution was concentrated under reduced pressure. The residue was dissolved in DMF (15 ml). To the solution, a mixture of 4-trifluoromethylbenzyl alcohol (373 mg, 2.12 mmol) and 1,1′-carbonyldiimidazole (344 mg, 2.12 mmol) in DMF (5 ml) stirred at room temperature for 3 hours was added followed by stirring at room temperature for 1 hour. The reaction mixture was poured into water and extracted with ethyl acetate. The organic phase was washed with a saturated saline solution and dried over magnesium sulfate. After filtration, the resulting filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (methylene chloride/methanol=50/1) and crystallized from methylene chloride-isopropyl ether to afford 4-trifluoromethylbenzyl (S)-4-[2-(N-methyl-2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethylamino)ethyl]piperazine-1-carboxylate (196 mg, yield 53%) as a white powder.

Provenance & Evidence