Citric Acid → (2S)-3-(2-(tert-butyldiphenylsilyloxy)ethoxy)-2-(1-(3-cyano-2-methylphenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-yloxy)-N-(5-methylpyridin-2-yl)propanamide

Participants

Reaction Conditions

Reaction Steps

Sodium hydride (60% in oil) (92 mg, 2.30 mmol) was added to (S)-3-(2-(tert-butyldiphenylsilyloxy)ethoxy)-2-hydroxy-N-(5-methylpyridin-2-yl)propanamide (Intermediate AU2) (500 mg, 1.04 mmol) in anhydrous THF (25 ml) at 0° C. under nitrogen. The resulting solution was stirred at 0° C. for 10 minutes and then 3-(4-chloro-1H-pyrazolo[3,4-d]pyrimidin-1-yl)-2-methylbenzonitrile (Intermediate AT2) (282 mg, 1.04 mmol) was added. The reaction mixture was allowed to warm to room temperature and stirred for 4 hours. The reaction mixture was neutralised with 1M citric acid and diluted with water and EtOAc. The organic layer was separated and the aqueous layer re-extracted with EtOAc. The combined organics were washed with saturated brine, dried (MgSO4) and evaporated. The crude product was purified by flash silica chromatography, eluting with 0 to 50% EtOAc in isohexane. No separation was achieved. The column was repeated with a 0-10% MeOH/DCM gradient. Still no separation! Mixed fractions were evaporated to dryness to afford (2S)-3-(2-(tert-butyldiphenylsilyloxy)ethoxy)-2-(1-(3-cyano-2-methylphenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-yloxy)-N-(5-methylpyridin-2-yl)propanamide (313 mg, 42.1%). m/z (ES+) (M+H)+=712.63; HPLC tR=3.85 min.

Provenance & Evidence