反应详情

185 g (1 mol) of 2,5-difluoro-4,6-dichloropyrimidine in 1800 ml of ethyl acetate were hydrogenated in a stirred stainless steel autoclave for 95 minutes at 30° C. and under a hydrogen pressure of 3.5 bar, with the addition of 110 g of triethylamine and 15 g of palladium on carbon (5% strength by weight). Thereafter, the solid components of the reaction mixture were filtered off, the residue was washed with ethyl acetate, and the wash liquid together with the filtrate was distilled under atmospheric pressure over a 30 cm packed column. After the solvent had been distilled off, 106 g of 2,5-difluoro-4-chloropyrimidine having a boiling point of 145° to 146° C. were obtained. The yield was accordingly 70.5% of theory. According to analysis by gas chromatography, the reaction product isolated had a purity of 94.7%.

1. filtrationThereafter, the solid components of the reaction mixture were filtered off
2. washthe residue was washed with ethyl acetate
3. distillationthe wash liquid together with the filtrate was distilled under atmospheric pressure over a 30 cm
4. distillationAfter the solvent had been distilled off