反应详情

A solution of 6-hydroxybenzofuran-3(2H)-one (3.00 g, 20.0 mmol) in ethanol (20 mL) was added with 1-tert-butoxycarbonylpiperazine (3.73 g, 20.0 mmol), and 37% aqueous formaldehyde (1.62 g, 20.0 mmol) at room temperature. The mixture was stirred overnight at room temperature, and then subjected to suction filtration, and the filtrate was concentrated. Crude product obtained by silica gel column chromatography (hexane/ethyl acetate) was recrystallized from ethyl acetate to obtain the objective tert-butyl 4-[(6-hydroxy-3-oxo-2,3-dihydrobenzofuran-7-yl)methyl]piperazine-1-carboxylate (3.51 g, 50%).

1. filtrationsubjected to suction filtration
2. concentrationthe filtrate was concentrated
3. customCrude product obtained by silica gel column chromatography (hexane/ethyl acetate)
4. customwas recrystallized from ethyl acetate