摘要 |
Chloropyrimidine compounds, such as 4,6-dichloro-2-ethoxypyrimidine, were prepared in good yield and good purity from the corresponding hydroxypyrimidine compounds in the absence of organic solvents and with a reduced amount of phosphorus oxychloride by carrying out the reaction in the presence of a trialkylamine compound and phosphorus trichloride. The additions of hydroxypyrimidine compound and trialkylamine compound could be made in segments. The chloropyrimidine compounds produced were recovered in an improved manner by adding chlorine to convert the chlorophosphoric acid by-products and phosphorus trichloride to phosphorus oxychloride, diluting the mixture with additional chloropyrimidine compound and removing the phosphorus oxychloride by distillation, combining the residue with water and a base, distilling the trialkylamine compound from the resulting mixture, and removing the aqueous phase. |