Allyl bromide → 1-(t-butoxycarbonyl)-4-(1-allyl-1H-benzimidazol-2-yl)[1,4]diazepane

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Reaction Conditions

Reaction Steps

Combine 1-t-butoxycarbonyl-4-(1H-benzimidazol-2-yl)[1,4]diazepane (0.8 g, 2.5 mmol) in dimethylformamide (10 mL). Add sodium hydride (0.13 g, 60% in oil, 3.25 mmol). After about 30 minutes, when the gas evolution ceases, add allyl bromide (0.35 mL 4.0 mmol). Heat to 75° C. After 4 hours, dilute with ethyl acetate and extract with a saturated aqueous sodium bicarbonate solution and then brine. Dry the organic layer over MgSO4, filter, and evaporate in vacuo to give 1-t-butoxycarbonyl-4-(1-(allyl)-1H-benzimidazol-2-yl)[1,4]diazepane: Rf =0.83 (silica gel, 10% methanol/dichloromethane/0.1% concentrated aqueous ammonia). Combine 1-t-butoxycarbonyl-4-(1-(allyl)-1H-benzimidazol-2-yl)[1,4]diazepane (0.9 g, 2.5 mmol) and ethanol (10 mL). Add aqueous hydriodic acid (10 mL, 57%). Heat to reflux. After 1 hour, cool to ambient temperature and dilute with diethyl ether (250 mL) and stir to give a solid. Collect the solid by filtration, rinse with diethyl ether, and dry to give the title compound.

Provenance & Evidence