Hydrochloric Acid → 4-Nitro-2-(trifluoromethyl)benzene-1-sulfonyl chloride

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Reaction Steps

Sodium nitrite (1.8 g, 26 mmol) was added portion wise to a stirred solution of 4-nitro-2-trifluoromethyl-phenylamine (5.0 g, 24 mmol) in acetic acid (37 ml) and HCl (concentrated, 7.5 ml) while maintaining the temperature below 15° C. This solution was then added drop wise to a stirred solution of saturated sulfur dioxide, copper (II) chloride (0.6 g, 4.5 mmol) and water (7.5 ml) in acetic acid (24 ml) at 5° C. The reaction mixture was allowed to warm to room temperature and poured over ice water and stirred for a further 15 minutes. The resulting precipitate was collected by filtration, washed with water and dried overnight in a vacuum oven to give the title compound (3.5 g, 71% yield) as a yellow solid which was used without further purification.

Provenance & Evidence