Salicylaldehyde oxime → 3-(4-Nitro-1H-pyrazol-1-yl)pyridine

Participants

Reaction Conditions

Reaction Steps

A flask which had been baked out and filled with argon was initially charged with 8.3 g (56.6 mmol) of copper oxide, 31.9 g (228 mmol) of salicylaldoxime, 200 g (1.71 mol) of 4-nitro-1H-pyrazole and 597 g (1.83 mol) of caesium carbonate. The flask was repeatedly evacuated and filled with argon. 218 g (800 mmol) of 3-bromopyridine and 1 l of DMF which had been degassed on a rotary evaporator were added. The reaction mixture was stirred at 130° C. overnight, cooled and filtered, and the DMF was removed on a rotary evaporator. The substance was dissolved in 1 l of ethyl acetate, and extracted with 2 l of H2O. The water phase was extracted twice with 500 ml of ethyl acetate. Filtration of the aqueous phase gave a green solid. 1 l of ethyl acetate and 100 ml of DMF were added thereto, and the mixture was heated to 50° C. Cooling was followed by filtration through Hyflo and washing with 500 ml of ethyl acetate. The filtrate was washed with 300 ml of water and 300 ml of saturated NaCl solution, dried over Na2SO4, filtered and concentrated. The solid was suspended in 100 ml of ethyl acetate, filtered and washed with ethyl acetate and methyl tert-butyl ether, and the beige solid (45 g) was dried on a rotary evaporator.

Provenance & Evidence