Triethyloxonium tetrafluoroborate → [(S)-1-(7-Cyano-6-fluoro-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 (1.12 g, 6.0 mmol) in DCM (7 mL) was added triethyloxonium tetrafluoroborate (969 mg, 5.1 mmol) and the reaction mixture stirred at RT for 3 h, during which time the solids dissolved. The reaction mixture was concentrated in vacuo and the residue dissolved in ethanol (7 mL). 3-Amino-6-fluoro-2-phenylaminobenzonitrile (400 mg, 1.8 mmol) was added and the reaction was heated at 75° C. for 1 h. 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 (411 mg, 61%). LCMS (Method C): RT=3.55 min, [M+H]+=381.

Provenance & Evidence