HCID 46197349, compound → HCID 67197784, compound

Participants

Reaction Steps

To a solution of 1-(2,6-difluorophenyl)hydrazine hydrochloride (12.38 g, 68.56 mmol) in anhydrous ethanol (70 mL) was added 2-(ethoxymethylene)malononitrile (8.791 g, 71.98 mmol) followed by triethylamine (10.01 mL, 71.98 mmol), and the contents stirred at RT for 10 min and then heated to reflux for 1.5 h. The contents were cooled to RT and solvents removed under reduced pressure. The resulting brown solid was stirred with 50 mL of water and 250 mL of EtOAc. The EtOAc layer was separated, washed with 50 mL of brine, dried and concentrated. The concentrated solid was stirred in 50 mL of hexanes for 5 min, filtered through a flitted funnel, and dried in a vacuum oven at 45° C. for 2 h to afford 5-amino-1-(2,6-difluorophenyl)-1H-pyrazole-4-carbonitrile as a brown solid. This material was used without further purification. MS (ES+): 221.1 (M+H)+. (B): A mixture of 5-amino-1-(2,6-difluorophenyl)-1H-pyrazole-4-carbonitrile (14 g, 64 mmol) in 50 mL of concentrated HCl was refluxed for 10 h. The reaction mixture was concentrated to half of its volume, cooled with an ice bath, pH adjusted to about 10 with 10 N NaOH, and extracted with 3×100 mL of EtOAc. The combined organic layers were washed with brine, dried and concentrated to afford 1-(2,6-difluorophenyl)-1H-pyrazol-5-amine as a brown amorphous solid. This material was used without further purification. MS (ES+): 196.1 (M+H)+.

Provenance & Evidence