To a solution of 3-fluoro-4-nitrobenzyl alcohol (2.97 g) in acetone (60 ml) was added Jones reagent (13 ml), prepared from chromic acid (26.7 g) and sulfuric acid (23 ml) in water (100 ml), dropwise at 0°C. The mixture was stirred on a ice-bath for 0.5 h and quenched with isopropanol (20 ml) to be concentrated in vacuo. The residue was dissolved in ethyl acetate (30 ml) and washed with water (30 ml X 3), and brine (30 ml X 1), successively. The organic layer was dried over sodium sulfate and concentrated in vacuo to obtain a yellow solid, that was triturated with hexane. 3-fluoro-4-nitrobenzoic acid as a pale yellow solid (2.94 g, 92%).
