Triethyloxonium tetrafluoroborate → {(S)-1-[6-fluoro-1-(1-methyl-1H-pyrazol-4-yl)-1H-benzoimidazol-2-yl]ethyl}carbamic acid tert-butyl ester

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Reaction Steps

Triethyloxonium tetrafluoroborate (0.35 g, 1.86 mmol) was added to a solution of ((S)-1-carbamoylethyl)carbamic acid tert-butyl ester (0.41 g, 2.22 mmol) in DCM (10 mL) at 20° C. under nitrogen and the resultant mixture stirred for 3 h then was concentrated in vacuo. The residue was dissolved in ethanol (10 mL) and 4-fluoro-N2-(1-methyl-1H-pyrazol-4-yl)-benzene-1,2-diamine (0.183 g, 0.89 mmol) added. The resultant solution was stirred at reflux for 16 h under nitrogen. The reaction mixture was concentrated in vacuo and the residue partitioned between DCM (×3) and saturated aqueous NaHCO3. The combined DCM extracts were dried (Na2SO4) and concentrated in vacuo. The resultant residue was purified by chromatography (SiO2, 0-5% (2M ammonia in methanol) in DCM) to give the title compound as a brown oil (0.274 g, 86%). LCMS (Method C): RT 2.77 min [M+H]+ 360.2.

Provenance & Evidence