Dimethylformamide → (1-(2-(t-butyldimethylsilyloxy)ethyl)-1H-benzimidazol-2-yl)(1-(ethoxycarbonyl)piperidin-4-yl)amine

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Reaction Steps

Combine (1H-benzimidazol-2-yl)(1-(ethoxycarbonyl)piperidin-4-yl)amine (4.00 g, 13.87 mmol) and dimethylformamide (12 mL) and tetrahydrofuran (60 mL). Cool in an ice-bath. Add sodium hydride (24 mg, 15.3 mmol). After 24 hours, add 2-(t-butyldimethylsilyloxy) ethyl iodide (3.97 g, 13.87 mmol). After 60 hours, add ice to quench the reaction. Evaporate the quenched reaction mixture in vacuo to remove most of the tetrahydrofuran. Partition the evaporated reaction mixture between water and ethyl acetate. Separate the layers and extract the organic layer three times with water. Dry the organic layer over MgSO4, filter, and evaporate in vacuo to give a residue. Chromatograph the residue on silica gel eluting sequentially with dichloromethane and then 5% methanol/dichloromethane to give (1-(2-(t-butyldimethylsilyloxy)ethyl)-1H-benzimidazol-2-yl)(1-(ethoxycarbonyl)piperidin-4-yl)amine: Rf=0.14 (silica gel, 40% ethyl acetate/dichloromethane).

Provenance & Evidence