Hydrochloric Acid → HCID 178504658, Verbindung

A solution of 5-(methylsulfonyl)-1H-indole (0.150 g, 0.768 mmol) in 1,4-dioxane (8 mL) was added with water (96 mL), and the mixture was stirred at room temperature. The reaction mixture was added with sodium nitrite (0.530 g, 7.68 mmol), and the mixture was cooled to 0° C. The reaction mixture was added dropwise with 3 N hydrochloric acid (1.54 mL, 4.62 mmol) at 0° C., and then the mixture was stirred at room temperature for 3 hours. The reaction mixture was extracted three times with ethyl acetate, and then the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. The organic layer was concentrated, and the resulting residue was purified by silica gel column chromatography (chloroform/methanol) to obtain 5-(methylsulfonyl)-1H-indazole-3-carboxaldehyde (0.0433 g, 25%).