Potassium Phosphate, Tribasic → 2-(5-Fluoropyridin-3-yl)-3-phenylpyrazolo[1,5-a]pyridine

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Reaction Conditions

Reaction Steps

A solution of 2-chloro-3-phenylpyrazolo[1,5-a]pyridine (37-1; 0.2 g, 0.88 mmol), (5-fluoropyridin-3-yl)boronic acid (0.15 g, 1.05 mmol), and potassium phosphate tribasic (0.66 g, 2.64 mmol) in tetrahydrofuran (10 mL) was degassed for 10 min. Then 2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl (0.065 g, 0.16 mmol) and palladium acetate (0.02 g, 0.08 mmol) were added and heated in a sealed tube at 100° C. for 18 h. The reaction mixture was then cooled to room temperature, filtered and concentrated under reduced pressure. Purification of the resulting residue by prep HPLC (Analytical Conditions: Column: Xbridge C18 (250 mm×4.6 mm×5 m), Mobile phase (A): water, Mobile phase (B): Acetonitrile, Flow rate: 1.0 mL/min, GradientT/% B:0/20, 8/50, 25/50, 27/20, 30/20) provided 2-(5-fluoropyridin-3-yl)-3-phenylpyrazolo[1,5-a]pyridine. 1H NMR (400 MHz, DMSO-d6) δ 8.81-8.79 (d, J=8.0 Hz, 1 H), 8.57-8.56 (d, J=4.0 Hz, 2 H), 7.76-7.73 (d, J=12.0 Hz, 1 H), 7.61-7.59 (d, J=8.0 Hz, 1 H), 7.49-7.45 (m, 1 H). MS (M+1): 290.1.

Provenance & Evidence