反应详情

To a solution of 129.2 g (0.69 mol) of 2,5-dichloro-3-nitropyridine in 1300 ml of dioxane is added 26.0 g of Raney-nickel, that has previously been washed with ethanol. This mixture is then hydrogenated with hydrogen under normal pressure at 20°-35° C. After uptake of 20% of the theoretical amount of hydrogen, another 30 g of washed Raney-nickel catalyst are added. After hydrogenating for 22 hours, the catalyst is filtered off, the solvent is evaporated and the residue is crystallized from hexane/ethyl acetate. Thus, 84.9 g of 3-amino-2,5-dichloropyridine (78% of the theory) are obtained, which melts at 129°-132° C.

1. washhas previously been washed with ethanol
2. customat 20°-35° C
3. additionAfter uptake of 20% of the theoretical amount of hydrogen, another 30 g of washed Raney-nickel catalyst are added
4. filtrationthe catalyst is filtered off
5. customthe solvent is evaporated
6. customthe residue is crystallized from hexane/ethyl acetate