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

Participants

Reaction Conditions

Reaction Steps

Trimethylaluminium (2M in hexane) (0.455 mL, 0.91 mmol) was added to 6-aminonicotinonitrile (104 mg, 0.87 mmol) in toluene (10 mL) cooled to 0° C. under nitrogen. The resulting solution was stirred at 0° C. for 20 minutes. (2S)-methyl 3-(2-(tert-butyldiphenylsilyloxy)ethoxy)-2-(1-(3-chloropyridin-2-yl)-1H-pyrazolo[3,4-d]pyrimidin-4-yloxy)propanoate (Intermediate AB2) (500 mg, 0.79 mmol) in toluene (2 mL) was added and the reaction was allowed to warm to room temperature. The temperature was increased to 60° C. and stirred for 4 hours, then heated at reflux for 24 hours. The reaction mixture was concentrated in vacuo and neutralised with citric acid (1M, aq) and then diluted with water (10 ml) and DCM (10 mL). The mixture was poured onto a phase separator and the organic layer was evaporated in vacuo. The crude product was purified by preparative HPLC (Waters XBridge Prep C18 OBD column, 5μ silica, 50 mm diameter, 150 mm length), using decreasingly polar mixtures of water (containing 0.1% formic acid) and MeCN as eluents. Fractions containing the desired compound were neutralised with MP-carbonate and evaporated to dryness to afford the product (100 mg, 17.6%). m/z (ES+) (M+H)+=719.51; HPLC tR=3.58 min.

Provenance & Evidence