Acetic Anhydride → 7-Methoxyindazole

Beteiligte Stoffe

Reaktionsschritte

To a solution of N-(2-methoxy-6-methylphenyl)acetamide (9.28 g, 51.8 mmol) in ethyl acetate (100 ml) are added acetic anhydride (14.7 mL, 156 mmol), tetrabutylammonium bromide (0.84 g, 2.61 mmol), potassium acetate (10.16 g, 104 mmol), and isoamyl nitrite (9.1 mL, 67.7 mmol), and the mixture is refluxed for 9 hours. After the reaction is completed, the solvent is evaporated under reduced pressure, and to the obtained residue is added 6N aqueous sodium hydroxide solution (100 mL). The mixture is stirred at room temperature for 1 hour. After the reaction is completed, the pH value of the mixture is adjusted to pH 7–8 with 3N hydrochloric acid, and the mixture is extracted with chloroform. The organic layer is dried over anhydrous magnesium sulfate, and the solvent is evaporated under reduced pressure. The obtained residue is purified by silica gel column chromatography (n-hexane/ethyl acetate=3/1→1/1) to give the title compound (3.95 g, yield: 51%).

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