Triethyloxonium tetrafluoroborate → [(S)-1-(3-Pyridin-2-yl-3H-imidazo[4,5-b]pyridin-2-yl)ethyl]carbamic acid tert-butyl ester

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Reaction Steps

Triethyloxonium tetrafluoroborate (1.08 g, 5.66 mmol) was added to a solution of ((S)-1-carbamoylethyl)carbamic acid tert-butyl ester (1.00 g, 5.33 mmol) in THF (15 mL) at 20° C. under nitrogen and the resultant mixture stirred for 2 h then concentrated in vacuo. A solution of N2-pyridin-2-yl-pyridine-2,3-diamine (0.62 g, 3.33 mmol) in ethanol (15 mL) was added to the residue and the resultant solution stirred at 75° C. for 16 h. The reaction mixture was concentrated in vacuo and the residue partitioned between DCM (3×30 mL) and saturated aqueous NaHCO3 (30 mL). The combined DCM extracts were dried (Na2SO4) and concentrated in vacuo. The resulting residue was purified by chromatography (SiO2 0-5% (2M ammonia in methanol) in DCM) to give the title compound as an oil (1.11 g, 98%). LCMS (method H): Rt 2.73 min, [M+H]+ 340.

Provenance & Evidence