Sulfuric Acid → 3-Hydroxy-2-methylbenzoic Acid

Participants

Reaction Conditions

Reaction Steps

A solution of 3-amino-2-methylbenzoic acid (43.1 g, 285 mmol), water (700 mL), and sulfuric acid (55 mL) was briefly heated to give a clear solution and then cooled to a temperature below 5° C. A solution of sodium nitrite (21 g, 300 mmol) in a minimal amount of water was added in portions while maintaining the internal temperature below 7° C. After stirring for about 30 minutes in an ice bath, urea (7 g) was added to discharge the excess nitrile. A chilled solution of 98% sulfuric acid (240 mL) in water (1000 mL) was added to the diazonium solution, and the combined reaction mixture was heated slowly to 90° C. Solid sodium hydroxide (410 mg) was slowly added. The mixture was extracted with ethyl acetate, and the organic layer was dried over sodium sulfate and evaporated to give 3-hydroxy-2-methylbenzoic acid as a yellow solid (44.4 g,˜100%).

Provenance & Evidence