Hydrochloric Acid → 6-Chloronaphthalene-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

Sodium nitrite (811 mg, 11.8 mmol) is added over a period of 15 minutes to concentrated sulfuric acid (10 mL) while stirring. The mixture is heated to 70° C. for 15 minutes. After cooling to room temperature, a solution of 6-amino-2-naphthoic acid (2 g, 10.7 mmol) in acetic acid (10 mL) is added dropwise at such a rate that the temperature is kept below 40° C. After stirring at 40° C. for an additional 30 minutes, the reaction mixture is poured into an ice-cooled solution of copper(I) chloride (2.54 g, 25.6 mmol) in concentrated HCl (30 mL). After stirring at 80° C. for 30 minutes, water (80 mL) is added. The precipitate is collected and purified by flash chromatography on silica gel (5% methanol in dichloromethane) to give 6-chloro-2-naphthoic acid as a brown solid.

Provenance & Evidence