反应详情

温度

50 °C

A mixture of 3-(benzyloxy)-6-methyl-4-oxo-4H-pyran-2-carboxylic acid (2.5 g, 9.6 mmol, 1.0 equiv), 1,1′-carbonyldiimidazole (2.49 g, 15.37 mmol, 1.6 equiv) in DMF (20 mL) was stirred at 50° C. for 5 h. The mixture was cooled to room temperature. Cyclobutylamine hydrochloride (1.24 g, 11.52 mmol, 1.2 equiv) and Et3N (1.74 mL, 12.48 mmol, 1.3 equiv) was added, and the mixture was stirred overnight at room temperature. The solvent was removed under reduced pressure. Purification by chromatography (1:1 hexanes/EtOAc, then EtOAc) provided the titled compound (2.76 g, 91.56%) as a yellow solid. M.p. 69.3-71.0° C.; 1H-NMR (CDCl3, 400 MHz) δ 1.51-1.72 (m, 4H, cyclobutyl H), 2.19-2.28 (m, 2H, cyclobutyl H), 2.37 (s, 3H, CH3), 4.39-4.41 (m, 1H, CH), 5.41 (s, 2H, OCH2Ph), 6.30 (s, 1H, CH), 7.39-7.49 (m, 5H, ArH), 7.86 (br, 1H, NH), and MS (m/z) 314 (M++1), 217, 91.

1. temperatureThe mixture was cooled to room temperature
2. stirringthe mixture was stirred overnight at room temperature
3. customThe solvent was removed under reduced pressure
4. customPurification by chromatography (1:1 hexanes/EtOAc