Sulfuric Acid → 3-Hydroxy-5-nitrobenzoic acid

Participants

Reaction Steps

To a solution of 3-amino-5-nitro-benzoic acid methyl ester (Example 313, 1.96 g, 10 mmol) in 23 mL of H2O and 5 mL of con. H2SO4 at 0° C., was added a solution of NaNO2 (Aldrich, 900 mg, 13 mmol) in 9 mL of H2O. After 50 min stirring, the resulting diazonium salt was added to a solution of 17 mL of H2O and 17 mL of con. H2SO4 at 90° C. After stirred at 90 ° C. for 90 min, the mixture was cooled to room temperature and brought to pH 3 with con. NH4OH. The mixture was extracted 3× with EtOAc (100 mL). The organic layers were washed twice with a brine solution (100 mL), dried over Na2SO4 and concentrated. The residue was purified by chromatography (5%-10% MeOH/CH2Cl2) to give 705 mg (39%) of product.

Provenance & Evidence