Oxalyl chloride → N-(5-cyano-2-fluorophenyl)imidazo[1,2-a]pyridine-3-carboxamide

Participants

Reaction Steps

To a stirring suspension of imidazo[1,2-a]pyridine-3-carboxylic acid (1) (3.0 g, 18.5 mmol) in anhydrous dichloromethane (50 mL) at 0° C. was added dropwise oxalyl chloride (4.84 mL, 55.5 mmol). Then, three drops of anhydrous DMF was added and the reaction mixture was stirred at room temperature for 15 minutes. The solvent was concentrated and the crude solid was added to a stirring solution of 3-amino-4-fluorobenzonitrile (48) (2.5 g, 18.5 mmol) in anhydrous pyridine (50 mL) at room temperature. The reaction was stirred for 20 minutes and quenched with water (200 mL) with stirring for another 10 minutes. Then the precipitate was filtered and dried in air to yield N-(5-cyano-2-fluorophenyl)imidazo[1,2-a]pyridine-3-carboxamide (49). 1H NMR (400 MHz, d6-DMSO) δ 10.40 (s, 1H), 9.43 (td, J=1.2, 6.8 Hz, 1H), 8.63 (s, 1H), 8.21 (dd, J=2.0, 7.2 Hz, 1H), 7.78-7.84 (m, 2H), 7.54-7.63 (m, 2H), 7.22 (dt, J=1.2, 6.8, 1H). MS m/z 281.1 (M+1)+.

Provenance & Evidence