Hydrochloric Acid → 1-(2,6-Dichloro-4-trifluoromethylphenyl)-5-formylamino-3-(1,2,4-oxadiazol-3-yl)-4-trifluoromethylsulfinylpyrazole

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Reaction Steps

1-(2,6-Dichloro-4-trifluoromethylphenyl)-5-hydroxyaminomethylideneamino-3-(1,2,4-oxadiazol-3-yl)-4-trifluoromethylsulfinylpyrazole (3.50 g, 6.69 mmol) was dissolved in 30 ml of acetone and 1.2 N hydrochloric acid (12 ml, 14.4 mmol) was added, and then the mixture was stirred at room temperature for 3 days. After 20 ml of water was added, the reaction mixture was neutralized with sodium hydrogencarbonate (powder). The solvent was distilled off and 20 ml of water and 100 ml of ethyl acetate were added, followed by partitioning. The aqueous layer was extracted with 30 ml of ethyl acetate and combined with the ethyl acetate layer, followed by washing with 50 ml of an aqueous saturated sodium hydrogencarbonate solution, then with 50 ml of an aqueous saturated sodium chloride solution. After drying over anhydrous magnesium sulfate, the solvent was distilled off to obtain a colorless amorphous. The amorphous was subjected to silica gel column chromatography [eluent: mixed solvent of ethyl acetate and chloroform (volume ratio=1:10)] to obtain 453 mg (0.89 mmol) of the title compound as a colorless crystal. Yield 13%.

Provenance & Evidence