2-Amino-5-chloropyridine → (2S)-3-(2-(tert-butyldiphenylsilyloxy)ethoxy)-N-(5-chloropyridin-2-yl)-2-(1-(2,3-dichlorophenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-yloxy)propanamide

Participants

Reaction Steps

Trimethylaluminium (2M in toluene) (0.638 mL, 1.28 mmol) was added to 5-chloropyridin-2-amine (164 mg, 1.28 mmol) in toluene (2 mL) under nitrogen. The resulting solution was stirred at room temperature for 15 minutes. (2S)-Methyl 3-(2-(tert-butyldiphenylsilyloxy)ethoxy)-2-(1-(2,3-dichlorophenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-yloxy)propanoate (Intermediate AR1) (425 mg, 0.64 mmol) in toluene (8 mL) was added sealed into a 20 mL microwave tube. The reaction was heated to 120° C. for 4 hours in the microwave reactor and cooled to RT. The reaction mixture was allowed to cool and concentrated in vacuo. The residue was neutralised with citric acid (1M, aq) and then diluted with water (30 mL) and extracted with EtOAc (2×50 mL). The combined organics were dried (MgSO4) and evaporated. The crude product was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in isohexane to afford (2S)-3-(2-(tert-butyldiphenylsilyloxy)ethoxy)-N-(5-chloropyridin-2-yl)-2-(1-(2,3-dichlorophenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-yloxy)propanamide (460 mg, 95%). m/z (ES+) (M+H)+=763; HPLC tR=3.94 min.

Provenance & Evidence