反应详情

33.4 g (0.186 mol) of 4-hydroxy-6-trifluoromethylpyrimidin-2-ylamine are added in portions (in each case ca. 5 g) to a mixture of 85 ml of phosphorus oxychloride and 47.5 ml of dimethylaniline and the mixture is heated at reflux until the added solid has dissolved. The mixture is then heated at reflux for a further 90 minutes. After cooling, the reaction mixture is added to ice water while observing the safety precautions for phosphorus oxychloride. The aqueous phase is extracted with methylene chloride, the organic phase is separated off and dried with sodium sulfate, and the drying agent is filtered off. Following concentration by evaporation, 47.8 g of a crude mixture are obtained. Following column chromatographic separation with ethyl acetate/heptane as eluent, 8.5 g of 4-chloro-6-trifluoromethylpyrimidin-2-ylamine were obtained (solid, 22% yield, purity 95%).

1. temperaturethe mixture is heated
2. temperatureat reflux until the added solid
3. dissolutionhas dissolved
4. temperatureThe mixture is then heated
5. temperatureat reflux for a further 90 minutes
6. temperatureAfter cooling
7. extractionThe aqueous phase is extracted with methylene chloride
8. customthe organic phase is separated off
9. dry with materialdried with sodium sulfate
10. filtrationthe drying agent is filtered off
11. concentrationconcentration
12. customby evaporation, 47.8 g of a crude mixture
13. customare obtained
14. customcolumn chromatographic separation with ethyl acetate/heptane as eluent