Pyridine → 2-methoxy-5-[1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-1,2,4-triazol-5-yl]pyridine

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Reaction Steps

Under ice-cooling, oxalyl chloride (0.206 mL, 2.4 mmol) and then cat. dimethylformamide were added to a suspension of 6-methoxynicotinic acid (367 mg, 2.4 mmol) in 3 mL of dichloromethane. The mixture was stirred at room temperature for 1.5 hour. The solvent was removed under reduced pressure and the residue was azeotropped with dioxane. A solution of 2,2,2-trifluoro-N′-(4-methoxyphenyl)ethanehydrazonamide (466 mg, 2.0 mmol) and pyridine (0.194 mL, 2.4 mmol) in 5 mL of dioxane was added to a suspension of the residue in 1 mL of dioxane. The mixture was refluxed with stirring for 4 hours. After cooling, the solvent was removed under reduced pressure. The desired product was purified by silica gal column chromatogaraphy (hexane-ethyl acetate 4:1) to give 2-methoxy-5-[1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-1,2,4-triazol-5-yl]pyridine (90 mg, 14.9% yield).

Provenance & Evidence