Triethyloxonium tetrafluoroborate → {(S)-1-[7-Cyano-6-fluoro-1-(5-fluoropyridin-3-yl)-1H-benzoimidazol-2-yl]-ethyl}carbamic acid tert-butyl ester

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Reaction Steps

To a suspension of ((S)-1-carbamoyl-ethyl)carbamic acid tert-butyl ester (1.81 g, 9.63 mmol) in DCM (20 mL) was added triethyloxonium tetrafluoroborate (1.54 g, 8.08 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 (20 mL). 3-Amino-6-fluoro-2-(5-fluoropyridin-3-ylamino)benzonitrile (948 mg, 3.86 mmol) was added and the reaction heated at 70° 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 give the title compound as an off white solid. LCMS (Method C): RT=3.20 min, [M+H-tBu]+=344, 100%, [M+H]+=400, 10%.

Provenance & Evidence