The general procedure for the synthesis of 2-amino-5-fluorophenol from 5-fluoro-2-nitrophenol is as follows: 5-fluoro-2-nitrophenol (2.50 g, 15.9 mmol, commercially available from e.g., Aldrich) was dissolved in ethanol (50 ml), and 10% palladium-carbon catalyst (980 mg) was added for the hydrogenation reaction, which lasted for 1.5 hours. Upon completion of the reaction, the catalyst was removed by filtration and the filtrate was concentrated. The solid residue obtained was dissolved in ether, followed by addition of an equal volume of cyclohexane. The ether was removed by vacuum distillation at room temperature to give a light gray solid product. The product was filtered and washed with cyclohexane to give 2-amino-5-fluorophenol (1.90 g, 94% yield). Elemental analysis measured values: C, 56.4; H, 4.8; N, 10.9. theoretical values (C6H6FNO): C, 56.7; H, 4.8; N, 11.0%.
