Water → Benzimidazole

Participants

Reaction Conditions

Reaction Steps

The sulfoxide solution was treated with triethylamine (25.4 mL). The mixture was cooled to 0-10° C. and 95% benzyl chloroformate (13.5 g) in dichloromethane (30 mL) was added while keeping the temperature below 10° C. After stirring for 2-3 hours, water (90 mL) was added. The phases were separated and the aqueous phase was extracted with dichloromethane (60 mL). The combined organic phases were washed with brine (60 mL) and saturated sodium bicarbonate (30 mL) and vacuum distilled to 90 mL. Ethyl acetate (180 mL) was added to the solution and vacuumed distilled to 90 mL. The solution was stirred while 150 mL of heptanes was added at 20-25° C. The suspension was cooled to 0-5° C. and maintained at this temperature for 2-3 hours. The suspension was filtered and the damp cake was pulped in ethyl acetate (30 mL) and heptanes (120 mL) for 1-2 hours. The suspension was filtered, washed with heptanes/ethyl acetate (4/1) (2×30 mL) and dried under vacuum at room temperature to afford 5/6-methoxy-1-benzyloxycarbonyl-2-[[4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-benzimidazole. Weight: 25.91 g. Yield: 59%. Ratio of 5- and 6-methoxy products: ˜3:2. The analytical data was consistent with the assigned structure.

Provenance & Evidence