Sodium Hydroxide → HCID 178526490, compound

Participants

Reaction Steps

A solution of bromine (0.75 ml, 14.6 mmol) in a 2N-aqueous sodium hydroxide solution (20 ml) was added dropwise to a mixed solution of 5-nitro-1H-indazole (3.26 g, 20.0 mmol), dioxane (60 ml) and a 2N-aqueous sodium hydroxide solution (30 ml) at 0° C. and stirred at 0° C. for 30 minutes and then at room temperature for 3.5 hours. An aqueous sodium hydrogensulfite solution was added thereto until a solid was precipitated, to terminate the reaction, followed by extraction with ethyl acetate. The extract solution was washed with an aqueous sodium thiosulfate solution and a saturated aqueous sodium chloride solution, dried over sodium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was suspended in ethyl acetate and extracted with a 0.1N-aqueous sodium hydroxide solution. After 6 times of the extraction, the combined aqueous layer was acidified with hydrochloric acid and then re-extracted with ethyl acetate. The extract solution was washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate, and then distilled under reduced pressure to remove the solvent, whereby 3-bromo-5-nitro-1H-indazole (0.93 g, 19%) was obtained.

Provenance & Evidence