反应详情

A solution of 5-fluoro-2-[(4-methoxy-3-methyl-2-pyridyl)methylthio]benzimidazole (5.5 g) in aqueous 47% HBr (50 ml) was heated for 24 hours under reflux. The reaction mixture was concentrated under reduced pressure. The residual oily substance was neutralized with a saturated aqueous solution of sodium hydrogencarbonate, to which was added ethyl acetate (50 ml) to give 5-fluoro-2-[(4-hydroxy-3-methyl-2-pyridyl)methylthio]benzimidazole (3.2 g, 62%). Recrystallization from ethanol afforded colorless needles, mp 232°-233° C.

1. temperatureunder reflux
2. concentrationThe reaction mixture was concentrated under reduced pressure
3. additionwas added ethyl acetate (50 ml)