Pyridine → Ethyl 1-cyclopropyl-3-(trifluoromethyl)-1H-pyrazole-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

Cyclopropyl boronic acid (11 g, 127 mmol), Copper acetate (17.4 g, 95.7 mmol), Pyridine (17.7 g, 223 mmol) and triethylamine (22.4 mL, 160 mmol) were added successively to a solution of ethyl 5-(trifluoromethyl)-1H-pyrazole-4-carboxylate (Preparation 100, 6.63 g, 31.9 mmol) in THF (70 mL) and the resulting mixture was allowed to stir at 60° C. for 36 hours. The reaction mixture was filtered over a celite bed and filtrate was concentrated in vacuo and diluted with EtOAc (200 mL). The organic layer was washed with 1N HCl (1×25 mL), brine (1×25 mL) and dried (Na2SO4) and evaporated in vacuo. The crude material was purified by silica gel column chromatography eluting with Hexane:EtOAc 85:15 to afford the title compound as brown solid (29%, 2.3 g).

Provenance & Evidence