2,6-Lutidine → 5-[(5-methoxy-3-pyridazinyl)oxy]-1-methyl-3-(trifluoromethyl)-1H-pyrazole-4-carboxaldehyde

Participants

Reaction Steps

5-Hydroxy-1-methyl-3-(trifluoromethyl)-1H-pyrazole-4-carboxaldehyde (3.0 g, 0.015 mole), 3-chloro-5-methoxypyridazine (2.3 g, 0.015 mole), 2,6-lutidine (2.8 g, 0.025 mole), and toluene (80 mL) were heated in a flask equipped with a short Vigreux column until 5 mL of solvent had distilled. The mixture was then held at reflux for 4 hours, cooled, poured into 1% hydrochloric acid, and extracted with a mixture of ether and ethyl acetate. The combined extracts were washed with 1% hydrochloric acid, 1% sodium hydroxide, 5% sodium chloride, then dried with magnesium sulfate, filtered and concentrated in vacuo. The residue was purified by silica gel chromatography using ethyl acetate/cyclohexane to give 5-[(5-methoxy-3-pyridazinyl)oxy]-1-methyl-3-(trifluoromethyl)-1H-pyrazole-4-carboxaldehyde (2.53 g, 55% yield) as a yellow solid.

Provenance & Evidence