反应详情

To a suspension of 7-(benzyloxy)-1-(2-methoxyethyl)-2-methyl-1H-benzimidazole-5-carboxylic acid (10.0 g, 29.4 mmol, Step 5) in methanol was added dropwise thionyl chloride (8.57 mL, 118 mmol) at room temperature, and the mixture was refluxed with stirring for 2 hours. After cooling to room temperature, the solvent was evaporated in vacuo. The residue was poured onto saturated sodium hydrogencarbonate aqueous solution, and the aqueous layer was extracted with dichloromethane. The combined organic layer was dried over magnesium sulfate, and concentrated in vacuo. The residue was suspended in diisopropyl ether (100 mL), and the precipitate was collected by filtration to afford the title compound as a gray solid (9.22 g, 85%).

1. temperaturethe mixture was refluxed
2. customthe solvent was evaporated in vacuo
3. additionThe residue was poured onto saturated sodium hydrogencarbonate aqueous solution
4. extractionthe aqueous layer was extracted with dichloromethane
5. dry with materialThe combined organic layer was dried over magnesium sulfate
6. concentrationconcentrated in vacuo
7. filtrationthe precipitate was collected by filtration