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

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Reaction Conditions

Reaction Steps

A solution 2-chloro-3-methylpyrazolo[1,5-a]pyridine (38-1; 0.15 g, 0.9 mmol), (5-fluoropyridin-3-yl)boronic acid (0.15 g, 1.05 mmol), and potassium phosphate tribasic (0.574 g, 2.7 mmol) in tetrahydrofuran (10 mL) was degassed for 10 min. Then 2-dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl (0.074 g, 0.18 mmol) and palladium acetate (0.02 g, 0.09 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: XTERRA C18 (250 mm×4.6 mm×5 μm) mobile phase(A):0.01% ammonia in water, mobile phase (B): acetonitrile flow rate: 1.0 mL/min time/% B: 0/20, 8/50, 25/50, 26/20, 30/20) provided 2-(5-fluoropyridin-3-yl)-3-methylpyrazolo[1,5-a]pyridine. 1H NMR (400 MHz, DMSO-d6) δ 8.88 (s, 1 H), 8.67-8.65 (d, J=8.0 Hz, 1 H), 8.06-8.03 (d, J=12 Hz, 1 H), 7.73-7.71 (d, J=8.0 Hz, 1 H), 7.23-7.20 (t, J=4.0 Hz, 1 H), 6.92-6.89 (t, J=4.0 Hz, 1 H), 2.45 (s, 3 H). MS (M+1): 228.0.

Provenance & Evidence