反应详情

7.5 g (0.042 mol) of 5-chloro-2-fluoro-3-nitropyridine are dissolved in 80 ml of ethanol. This solution is hydrogenated with hydrogen, in the presence of 1 g of Raney nickel catalyst, under normal pressure and at a temperature in the range from 20° to 25° C. After a hydrogenation period of 20 hours, the catalyst is removed and the solvent is evaporated off. The residue is taken up in ethyl acetate and the resultant solution is filtered through a layer of silica gel. The solvent is evaporated off and the residue is triturated in hexane. The precipitate is subsequently filtered and dried, affording 4.7 g (76%) of 3-amino-5-chloro-2-fluoropyridine, m.p. 74° C.

1. customAfter a hydrogenation period of 20 hours, the catalyst is removed
2. customthe solvent is evaporated off
3. filtrationthe resultant solution is filtered through a layer of silica gel
4. customThe solvent is evaporated off
5. customthe residue is triturated in hexane
6. filtrationThe precipitate is subsequently filtered
7. customdried