反应详情

温度

90 °C

A mixture of 5-methyl-1,3-dihydrobenzimidazol-2-one (2) (24.4 g) and phosphoryl chloride (245 mL) was stirred at 90° C. for 5 hr. After cooling to room temperature, chloroform (250 mL) was added to the reaction mixture. After stirring at room temperature, the resulting precipitate was collected by filtration, and washed 5 times with chloroform (100 mL). To the precipitate was added a mixture of ethyl acetate and saturated sodium hydrogen carbonate solution. After stirring at room temperature, the organic phase was successively washed with water and brine, and dried over magnesium sulfate. The solvent was evaporated under reduced pressure. The residue was powdered with hexane and diisopropyl ether to give 2-chloro-5-methyl-1H-benzimidazole (3) (20.4 g).

1. temperatureAfter cooling to room temperature
2. stirringAfter stirring at room temperature
3. filtrationthe resulting precipitate was collected by filtration
4. washwashed 5 times with chloroform (100 mL)
5. additionTo the precipitate was added
6. additiona mixture of ethyl acetate and saturated sodium hydrogen carbonate solution
7. stirringAfter stirring at room temperature
8. washthe organic phase was successively washed with water and brine
9. dry with materialdried over magnesium sulfate
10. customThe solvent was evaporated under reduced pressure