Citric Acid → (2S)-methyl 3-(2-(tert-butyldiphenylsilyloxy)ethoxy)-2-(1-(5-fluoro-2-methylphenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-yloxy)propanoate

Participants

Reaction Conditions

Reaction Steps

60% Sodium hydride (156 mg, 3.89 mmol) was added to (S)-methyl 3-(2-(tert-butyldiphenylsilyloxy)ethoxy)-2-hydroxypropanoate (Intermediate AB3) (1119 mg, 2.78 mmol) in anhydrous THF (15 mL) at 0° C. under nitrogen. The resulting solution was stirred at 0° C. for 10 minutes and then 4-chloro-1-(5-fluoro-2-methylphenyl)-1H-pyrazolo[3,4-d]pyrimidine (Intermediate AK3) (730 mg, 2.78 mmol) was added. The reaction mixture was allowed to warm to room temperature and stirred for 1 hour. The reaction mixture was neutralised with 1M citric acid and the majority of the THF removed in vacuo. The residue was diluted with water (20 mL) and EtOAc (100 mL). The organic layer was separated and the aqueous layer re-extracted with EtOAc (100 mL). The combined organics were washed with saturated brine (75 mL), dried (MgSO4) and evaporated. The crude product was purified by flash silica (120 g) chromatography, elution gradient 0 to 20% EtOAc in isohexane to afford the product (932 mg, 53.3%). 1H NMR (400 MHz, DMSO) δ 0.94 (9H, s), 2.03 (3H, s), 3.80-3.65 (7H, m), 4.16-4.03 (2H, m), 5.89 (1H, dd), 7.46-7.33 (8H, m), 7.54-7.48 (1H, m), 7.65-7.61 (4H, m), 8.48 (1H, s), 8.59 (1H, s); m/z (ES+) (M+H)+=629; HPLC tR=3.41 min.

Provenance & Evidence