反应详情

4N Hydrogen chloride in ethyl acetate (4 mL) was added to a solution of benzyl 4-[(3-amino-3-oxopropyl)(tert-butoxycarbonyl)amino]piperidin-1-carboxylate (3.38 g) obtained in Example 45c) in ethyl acetate (16 mL), and the mixture was stirred at room temperature for 15 hours. The white solid (2.73 g) formed was collected by filtration. A solution of the resulting white solid (1.0 g), CDI (0.47 g) and DBU (0.89 g) in dichloroethane (30 mL) was refluxed for 15 hours. The reaction mixture was washed with an aqueous 5% citric acid solution and saturated saline solution, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate) to obtain the title compound (0.21 g, 21%) as a white powder.