Pyridine → 4-[3-(2,5-Dichloro-4,6-dimethyl-3-pyridinyl)-1,2,4-oxadiazol-5-yl]-2-methoxy-6-nitrophenol

Participants

Reaction Conditions

Reaction Steps

In a second vessel, (Z)-2,5-dichloro-N′-hydroxy-4,6-dimethylnicotinimidamide (201.2 g, 1.24 eq) is suspended in 1,4-dioxane (720 mL, 4.5 vol) and the suspension is cooled to 10° C. The residue of example 3e in 1,4-dioxane is added slowly maintaining the temperature below 20° C. A clear orange solution is formed. After complete addition, the reaction mixture is stirred at 20° C. for 1 hour. Pyridine (483.7 mL, 8 eq) is then charged and the reaction mixture is heated slowly to 115° C. The mixture is stirred at 115° C. for 6 hours. The solution is then cooled to 20° C. Dioxane/pyridine is distilled off.

Provenance & Evidence