4-Fluoro-3-nitroaniline

70-34-8

364-76-1

369-36-8

Example 43: General procedure for the synthesis of 4-fluoro-3-nitroaniline and 2-fluoro-5-nitroaniline from 2,4-dinitrofluorobenzene. A hydrogenation reaction was carried out according to the method described in Example 25 using 5% rhodium/alumina as a catalyst. This was done as follows: 18.61 g (0.10 mol) of 2,4-dinitrofluorobenzene was dissolved in a solvent mixture of 100 ml of glacial acetic acid and 100 ml of anhydrous ethanol in the presence of an alumina hydrogenation catalyst containing 0.50 g of rhodium. The hydrogen pressure was maintained at 370 psi during the reaction and the reaction time was 2 hours. Upon completion of the reaction, the product was separated by column chromatography to afford 2.79 g of 2-fluoro-5-nitroaniline in 17.6% yield. In addition, 0.85 g of 4-fluoro-3-nitroaniline was recovered as a second fraction.