Methanol → 1-ethoxycarbonyl-4-(1H-benzimidazol-2-yl)[1,4]diazepane

Participants

Reaction Conditions

Reaction Steps

Combine 1-ethoxycarbonyl[1,4]diazepane (18.0 g, 104 mmol) and 2-chlorobenzimidazole (7.93 g, 52 mmol). Heat to 130° C. After 4 hours, cool to ambient temperature and add hot methanol to dissolve the reaction mixture. Add a saturated aqueous solution of sodium bicarbonate (150 mL) and concentrate in vacuo to remove most of the methanol. Combine the aqueous reaction mixture and 95/5 diethyl ether/ethyl acetate. Separate the aqueous layer and extract three times with dichloromethane. Combine the dichloromethane layers, dry over Na2SO4, filter, and evaporate in vacuo to give a residue. Triturate the residue with ethyl acetate (100 mL) to give a solid. Chromatograph on silica gel eluting with 10% methanol/dichloromethane/0.1% concentrated aqueous ammonia to give a residue. Triturate that residue with 9/1 diethyl ether/ethyl acetate to give a solid. Collect solid by filtration and dry in vacuo to give 1-ethoxycarbonyl-4-(1H-benzimidazol-2-yl)[1,4]diazepane: mp; 161-162° C.

Provenance & Evidence