Water → HCID 23081653, compound

Participants

Reaction Steps

2-(4-tert-Butoxycarbonylpiperazin-1-yl)methyl-2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazole prepared in Example 306 (500 mg, 1.36 mmol) was dissolved in trifluoroacetic acid (10 ml) followed by stirring at room temperature for 3 hours. The reaction mixture was concentrated under reduced pressure, and added methylene chloride (1 ml) and triethylamine (1 ml). The solution was stirred at room temperature for 5 minutes, and then concentrated under reduced pressure. The residue was dissolved in methylene chloride. To the solution, 2-chlorobenzoxazole (0.19 ml, 1.63 mmol) and triethylamine (0.23 ml, 1.63 mmol) were added followed by stirring at room temperature for 1 hour. The reaction mixture was poured into water, and extracted with methylene chloride. The organic phase was washed with a saturated saline solution, dried over magnesium sulfate and then filtered. The filtrate was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (methylene chloride/methanol=100/1) and crystallized from methylene chloride-diisopropyl ether to afford 2-[4-(2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl)piperazin-1-yl]benzoxazole (325 mg, yield 62%) as a white powder.

Provenance & Evidence