Water → 2-(3-Fluorophenyl)-6-(trifluoromethyl)pyrazolo[1,5-A]pyridine

Participants

Reaction Steps

To a suspension of 1-(3-fluorophenyl)-2-(5-trifluoromethyl-2-pyridinyl)ethanone oxime (10.0 g, 33.53 mmol) in DME (38 ml) was added MsCl (2.6 ml, 33.53 mmol) at 0° C. The suspension was stirred for 15-20 min and then Et3N (9.3 ml, 67.1 mmol) dissolved in DME (4 ml) was added dropwise at a rate to maintain the temperature ≦5° C. After the addition was complete, the suspension was warmed to room temperature and stirred for 1 hour. Additional Et3N (0.47 ml, 3.35 mmol) was added and the solution was stirred for 15 min at 30-35° C. The suspension was cooled to room temperature and filtered to remove the salts. The cake was washed with twice with DME (10 ml) and the filtrate was transferred to a clean reaction flask. To the filtrate was added FeCl2 (42 mg, 0.34 mmol) at room temperature. The solution was heated to 70° C. and stirred for 30 min. After cooling the solution to 40° C., H2O was added (80 ml). The resultant suspension was cooled to 0-5° C. and stirred for 30 min. The solid was isolated by filtration and partially dried via airflow. The solid was further dried under reduced pressure (20 in Hg Vacuum) at 50° C. to afford 7.91 g (84%) of the title compound as a beige solid.

Provenance & Evidence