反应详情

Part 2. To a chilled solution of methyl 3-amino-4-[(tert-butoxy)carbonylamino]benzoate (0.40 g, 1.5 mmol) in CH2Cl2 (10 mL) and triethylamine (0.21 mL, 1.5 mmol) was added a solution of triphosgene (161 mg, 0.54 mmol) in CH2Cl2 (6 mL) over 5 min. The reaction was stirred at room temperature for 2 hr, diluted with CH2Cl2, washed with water and brine, dried over sodium sulfate and concentrated in vacuo. The crude product was purified by silica gel chromatography using 50% ethyl acetate in CH2Cl2 as eluent to give methyl 1-[(tert-butyl)oxycarbonyl]-2-oxo-(3H)—benzimidazole-5-carboxylate (0.27 g, 61%).

1. washwashed with water and brine
2. dry with materialdried over sodium sulfate
3. concentrationconcentrated in vacuo
4. customThe crude product was purified by silica gel chromatography