Acetic Acid → HCID 69479057, compound

Participants

Reaction Steps

A mixture of tert-butyl (S)-4-(6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl)piperazine-1-carboxylate prepared in Example 394 (7.2 g, 20.26 mmol), trifluoroacetic acid (24 ml) and methylene chloride (72 ml) was stirred at room temperature for 2 hours. The reaction mixture was concentrated under reduced pressure, and the residue was dissolved in methylene chloride (100 ml), then neutralized with triethylamine (20 ml, 143.49 mmol). The solution was concentrated under reduced pressure, and the residue was dissolved in methanol (72 ml). To the solution, 4-phenylbenzaldehyde (7.38 g, 40.52 mmol), sodium cyanotrihydroborate (3.82 g, 60.78 mmol), and acetic acid (3.48 ml, 60.78 mmol) were added in this order followed by stirring at room temperature for 24 hours. The precipitates were filtered off, washed with methanol, and purified by silica gel column chromatography (methylene chloride/methanol=10/1) to afford (S)-2-[4-(biphenyl-4-ylmethyl)piperazin-1-ylmethyl]-6-nitro-2,3-dihydroimidazo[2,1-b]oxazole (5.52 g, yield 65%) as a yellow powder.

Provenance & Evidence