Potassium Carbonate → tert-butyl 3-(4-ethoxy-4-oxobutyl)-4-(1-ethylpropyl)-2-oxo-2,3-dihydro-1H-benzimidazole-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence