4-Toluenesulfonyl chloride → 2-(1-Benzofuran-5-yl)-5-methyl-1,3,4-oxadiazole

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Reaction Steps

A solution of N′-acetyl-1-benzofuran-5-carbohydrazide (20.7 g, 36.2 mmol) and p-toluenesulfonyl chloride (36.2 g, 190 mmol) in pyridine (200 mL) was stirred under an argon atmosphere at 80° C. for 16 hr. After cooling, the reaction mixture was diluted with ethyl acetate, washed water, 2 M hydrochloric acid, saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was purified by basic silica gel column chromatography (tetrahydrofuran) and recrystallized from tetrahydrofuran to give the title compound (16.0 g, yield 84%) as colorless crystals.

Provenance & Evidence