反应详情

温度

85 °C

To a solution of tert-butyl 4-(1-ethylpropyl)-2-oxo-2,3-dihydro-1H-benzimidazole-1-carboxylate (Reference Example 7; 10.37 g, 34.11 mmol) in N,N-dimethylformamide (100 mL) was added potassium carbonate (5.18 g, 37.52 mmol) and ethyl 4-bromobutyrate (8.55 g, 37.52 mmol), and the mixture was stirred at 80-90° C. overnight. The reaction solution was concentrated to dryness and diluted with water (150 mL). The resulting mixture was extracted with ethyl acetate (100 mL×2). The combined extracts were washed with water (80 mL×2), brine (100 mL), dried over anhydrous sodium sulfate and concentrated in vacuo to give 19.3 g of crude tert-butyl 3-(4-ethoxy-4-oxobutyl)-4-(1-ethylpropyl)-2-oxo-2,3-dihydro-1H-benzimidazole-1-carboxylate, which was used for the next step without further purification.

1. concentrationThe reaction solution was concentrated to dryness
2. additiondiluted with water (150 mL)
3. extractionThe resulting mixture was extracted with ethyl acetate (100 mL×2)
4. washThe combined extracts were washed with water (80 mL×2), brine (100 mL)
5. dry with materialdried over anhydrous sodium sulfate
6. concentrationconcentrated in vacuo