Potassium Carbonate → Methyl 6-iodo-2-phenylpyrazolo[1,5-a]pyridine-3-carboxylate

Participants

Reaction Steps

Dichloromethane (10 mL) and 3-Iodopyridine (928 mg, 4.53 mmol) were charged to a 100 mL, round-bottomed flask equipped with a magnetic stir bar. This colorless solution was cooled on an ice bath and O-(mesitylsulfonyl)hydroxylamine (975 mg, 4.53 mmol) in dichloromethane (10 mL) was added dropwise over 5 minutes. After to stirring at room temperature for 30 minutes, the solvent was removed by rotary evaporation to give a white solid. Methyl phenylpropiolate (1000 mg, 6.24 mmol) was added in dimethylformamide (9 mL). Potassium carbonate (2504 mg, 18.12 mmol) was added. Reaction slowly turned dark green. After stirring at room temp for 2 hours, the reaction was poured into diethyl ether (300 mL and extracted 8×25 mL water. The solvent was removed from the organic portion by rotary evaporation. The crude product was dissolved in a minimum amount of dichloromethane and charged to a 90 g “Single Sep” silica gel cartridge and eluted with 0 to 40% ethyl acetate in hexanes over 1000 mL. The title compound (200 mg, 12%) was isolated as an orange solid. 1H NMR (500 MHz, CHLOROFORM-D) δ ppm 3.83 (s, 3H) 7.46 (m, 3H) 7.59 (dd, J=9.16, 1.53 Hz, 1H) 7.7.5 (m, 2H) 8.00 (dd, J=9.31, 0.76 Hz, 1H) 8.82 (s, 1H). LCMS: 2.4 minutes, M+1=379.

Provenance & Evidence