Ammonium formate → ethyl 3-(6-amino-1H-benzimidazol-1-yl)-3-phenylpropanoate

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Reaction Steps

To a mixture of ethyl-3-(5-nitro-1H-benzimidazol-1-yl)-3-phenyl-2-propenoate and ethyl-3-(6-nitro-1H-benzimidazol-1-yl)-3-phenyl-2-propenoate (5.34 g, 15.8 mmol) in a mixture of ethanol and water (10:1, 66 mL) was added palladium on carbon (801 mg, 10% w/w Pd) and ammonium formate (6.0 g, 95 mmol). The suspension was heated to reflux, and was stirred at this temperature for 1.5 hours. The reaction mixture was allowed to cool to room temperature, then filtered through Celite®, and the filter pad washed several times with ethanol. The combined filtrates were evaporated in vacuo, and the residue was purified by flash column chromatography on silica gel, eluting with a mixture of dichloromethane and methanol (99:1) to give, in order of elution, ethyl 3-(6-amino-1H-benzimidazol-1-yl)-3-phenylpropanoate, [LCMS (Method A, Mobile Phase I) RT=3.33 min, MH+ 310] and ethyl 3-(5-amino-1H-benzimidazol-1-yl)-3-phenylpropanoate (1.96 g), [LCMS (Method A, Mobile Phase I) RT=3.35 min, MH+ 310].

Provenance & Evidence