Dimethylformamide → 4-(2-fluorophenyl)-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

11.08 ml of N,N-dimethylformamide was slowly added dropwise to 11.03 ml of POCl3 were at 0-5° C. while stirring and, after about 5 minutes a solution of 2-fluorophenylacetic acid (6 g, 38.9 mmol) in 20 ml of N,N-dimethylformamide was added dropwise. The mixture was then heated at 70° C. for about 17 hours. The mixture was subsequently quenched with ice-water and the mixture was made alkaline by adding NaOH. The resulting solid was filtered off, the solution was extracted with dichloromethane, and the organic phase was dried and concentrated. The oil obtained in this way was directly dissolved in 50 ml of ethanol. 7.3 ml of hydrazine hydrate were added, and the reaction mixture was heated at 55° C. for 3 hours. After the reaction was complete, the solvent was evaporated and the remaining solid was stirred with water and then dried. 2.65 g of 4-(2-fluorophenyl)-1H-pyrazole were obtained.

Provenance & Evidence