Sulfuric Acid → 3-Fluoro-4-nitrobenzoic acid

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Reaction Steps

To a solution of 3-fluoro-4-nitrotoluene (22.45 g, 144.7 mmol) and sodium dichromate dihydrate (60.38 g, 202.6 mmol) in water at 0° C. was added concentrated sulfuric acid (140 mL) dropwise over 3 h. When the addition was complete, the solution was allowed to warm to room temperature over 1 h, and then brought to 90° C. for 1 h. The mixture was allowed to cool to room temperature, diluted with 300 mL water and extracted with ethyl acetate (3×250 mL). The combined organic extracts were concentrated down to 300 mL and extracted with 1 N NaOH (3×250 mL). The aqueous extracts were acidified with 6 N HCl and extracted with ethyl acetate (3×300 mL). The combined organic extracts were dried over MgSO4 and concentrated to give a gummy solid. Trituration with hexane gave the 3-fluoro-4-nitrobenzoic acid as a solid that was collected by filtration (6.51 g, 24%).

Provenance & Evidence