Trifluoroacetic acid → HCID 23081374, compound

Participants

Reaction Steps

A mixture of tert-butyl 4-(2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl)-homopiperazine-1-carboxylate prepared in Example 645 (250 mg, 0.655 mmol) and trifluoroacetic acid (10 ml) was stirred at room temperature overnight. The reaction mixture was concentrated under reduced pressure, the residue was dissolved in methylene chloride (10 ml). To the solution, triethylamine (0.27 ml, 1.96 mmol) and benzyl chloroformate (0.19 ml, 1.31 mmol) were added followed by stirring at room temperature for 3 hours. To the reaction mixture, water was added, and the mixture was extracted with methylene chloride. The organic phase was 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/ethyl acetate=1/1) to afford a light yellow oil. The resulting oil was dissolved in ethyl acetate. To the solution, a saturated hydrochloric acid/ethyl acetate solution was added, and the precipitates were filtered off to afford benzyl 4-(2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl)homopiperazine-1-carboxylate hydrochloride (246 mg, yield 83%) as a white powder.

Provenance & Evidence