Water → ethyl 3-(2-((4-(N-(hexyloxycarbonyl)carbamimidoyl)phenylamino)methyl)-1-methyl-N-(pyridin-2-yl)-1H-benzo[d]imidazole-5-carboxamido)propanoate

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Reaktionsschritte

10.0 g (16 mmol) of crude ethyl 3-{[(2-{[(4-{carbamimidoyl}phenyl)amino]methyl}-1-methyl-1H-benzimidazol-5-yl)carbonyl](pyridin-2-yl)amino}propanoate (HPLC purity, method 3: 82.1%) as obtained in Example 2, step (g), was suspended in a mixture of 7.07 g (51 mmol) of potassium carbonate, 42.7 mL of water and 427 mL of tetrahydrofuran. The mixture was stirred at room temperature for 30 minutes. After cooling to 15° C., 2.81 g (17 mmol) of hexyl chloroformate were added while keeping the reaction temperature between 15 to 20° C. The resulting mixture was stirred at room temperature for 2 hours. The mixture was filtered and the solid was discarded. The organic phase was extracted from the mother liquors, and the solvent was removed by vacuum distillation. The residue was dissolved in 200 mL of dichloromethane, and residual aqueous phase was extracted. The organic phase was dried with anhydrous sodium sulfate. The solvent was removed under vacuum to yield 11.0 g of crude dabigatran etexilate as a red slurry. Purity (HPLC, method 1): 87.3%. Content of compound (A2) (HPLC, method 1): 9.8%.

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