Triethyloxonium tetrafluoroborate → [(S)-1-(7-Cyano-6-fluoro-1-pyridin-2-yl-1H-benzoimidazol-2-yl)ethyl]carbamic acid tert-butyl ester

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Reaction Steps

To a suspension of ((S)-1-carbamoylethyl)carbamic acid tert-butyl ester (820 mg, 4.4 mmol) in DCM (7 mL) was added triethyloxonium tetrafluoroborate (877 mg, 4.6 mmol) and the reaction mixture stirred at RT for 2 h, during which the solids dissolved. The reaction mixture was concentrated in vacuo and the residue dissolved in ethanol (7 mL). 3-Amino-6-fluoro-2-(pyridin-2-ylamino)benzonitrile (620 mg, 2.7 mmol) was added and the reaction heated at 75° C. for 16 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 (563 mg, 54%). LCMS (Method C): RT=3.20 min, [M+H]+=382.

Provenance & Evidence