Triethyloxonium tetrafluoroborate → [(S)-1-(6-Fluoro-7-methoxy-1-phenyl-1H-benzoimidazol-2-yl)ethyl]-carbamic acid tert-butyl ester

Participants

Reaction Steps

To a suspension of ((S)-1-carbamoylethyl)carbamic acid tert-butyl ester (779 mg, 4.1 mmol) in DCM (5 mL) was added triethyloxonium tetrafluoroborate (671 mg, 3.5 mmol) and the reaction mixture stirred at RT for 2 hours, during which the solids dissolved. The reaction mixture was concentrated in vacuo and the residue dissolved in ethanol (5 mL). 4-Fluoro-3-methoxy-N2-phenylbenzene-1,2-diamine (283 mg, 1.2 mmol) was added and the reaction heated at 70° C. for 1.5 hours. The reaction mixture was concentrated in vacuo, the residue dissolved in water and the product extracted with EtOAc (3×20 mL). The combined organic extracts were washed with brine, dried (MgSO4) and concentrated in vacuo. The resultant residue was subjected to flash chromatography (SiO2, eluting with 0-100% EtOAc in cyclohexane) to yield the title compound as a white solid (349 mg, 74%). LCMS (Method C): RT=3.52 min, [M+H]+=386.

Provenance & Evidence