4-Chlorobenzenesulfonyl chloride → 1-(4-chlorobenzenesulfonyl)-5-difluoromethoxy-2-[(3,4-dimethoxy-2-pyridyl)methylsulfinyl]-1H-benzimidazole

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Reaction Conditions

Reaction Steps

5-Difluoromethoxy-2-[(3,4-dimethoxy-2-pyridyl)methylsulfinyl]-1H-benzimidazole, sodium salt sesquihydrate (432 mg, 1 mmole) was suspended in 30 ml of dichloromethane in the presence of anhydrous sodium carbonate (100 mg). 4-Chlorobenzenesulfonyl chloride (211 mg, 1 mmole) was added to the suspension and stirred at 4° C. overnight. The organic layer was separated by filtration and concentrated under reduced pressure. The residual solid was crystallized from dichloromethane-ethyl ether-heptane. 417 mg of 1-(4-chlorobenzenesulfonyl)-5-difluoromethoxy-2- [(3,4-dimethoxy-2-pyridyl)methylsulfinyl]-1H-benzimidazole was obtained. Yield 74.5%.

Provenance & Evidence