Trifluoroacetic acid → (S)-N-(5-chlorobenzofuran-2-ylmethylene)-N-[4-(2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl)piperazin-1-yl]amine

関与物質

反応手順

To a mixture of tert-butyl (S)-[4-(2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl)piperazin-1-yl]carbamate prepared in Example 503 (0.20 g, 0.523 mmol) and 5-chlorobenzofuran-2-carbaldehyde (0.113 g, 0.628 mmol) and methylene chloride (4 ml), trifluoroacetic acid (0.4 ml) was added followed by stirring at room temperature for 2 hours. To the reaction mixture, a saturated sodium hydrogencarbonate solution was added followed by extraction with methylene chloride. The organic phase was washed with a saturated saline solution, dried over sodium sulfate and then filtered. The resulting filtrate was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (methylene chloride/ethyl acetate=4/1) to afford (S)-N-(5-chlorobenzofuran-2-ylmethylene)-N-[4-(2-methyl-6-nitro-2,3-dihydroimidazo[2,1-b]oxazol-2-ylmethyl)piperazin-1-yl]amine (0.137 g, yield 59%) as a light yellow powder.

情報源と証拠